This is the second installment of RaceDepartment's season review of the 2015 Formula One World Championship. In this installment, we will briefly review and assess the drivers who finished in the top ten in this year's World Drivers' Championship, led by the three-time and still reigning champion, Lewis Hamilton. Each driver in this series of reviews is rated on a 1-10 scale. Grades are given out based not only on results in the championship standings, but also factoring in intra-team performance, recent history of performance, and other extraneous factors. As a standard yet necessary disclaimer: The final grade scores at the end of each brief assessment are entirely subjective and may not reflect the criteria of the staff as a whole. As was the case in 2014, Mercedes AMG Petronas F1 Team were the dominant constructor, spearheaded by the charge of their Anglo-German driver combination - who led a field of contenders including two former World Champions at Ferrari, and a 24 Hours of Le Mans champion. 1st: Lewis Hamilton - Mercedes AMG Petronas F1 Team This was the most decisive of Lewis Hamilton's three World Drivers' Championships so far. He became the first in a long line of champions from the UK to successfully defend their championship. He led the sport in every category from race wins and pole positions, to hair styles and pop albums. By the end of 2015, he was only behind Michael Schumacher and Alain Prost on the all-time Grand Prix victories list. He was a dominant performer, but not a perfect one as shown down the stretch of 2015, and also in Monaco, Hungary, and Singapore. But that only demonstrates how great his nearest challengers, Vettel and Rosberg, are as his rivals. Lewis Hamilton's personality might rub some the wrong way - he takes losing as poorly as he revels in victory, his lifestyle clashes with the ideals of most of F1's supporters - but he is a truly great champion at the peak of his powers, and that's to be respected above all. Grade: 9.5/10 2nd: Nico Rosberg - Mercedes AMG Petronas F1 Team It's incredible to think that a year in which Nico Rosberg set new career-highs for points and wins in a season and took a three-peat in the principality of Monaco could be viewed as a let-down from 2014, but such is the case when Rosberg's intermittent shortfalls came at such inopportune times. Mechanical DNFs at Italy and Russia basically knocked Nico out of title contention late in the year as Hamilton never missed a beat when the stakes were highest. But then Rosberg closed out 2015 with six straight pole positions and a hat trick of victories to remind the world that he's still one of the best in this sport. Truth be told, there are many great and respected champions who can't match Nico Rosberg's cumulative accomplishments. If Nico takes his momentum into 2016, he may lift that piano off his back and bask in the championship glory he's deserved for years. Grade: 9/10 3rd: Sebastian Vettel - Scuderia Ferrari As hard as it was to believe that Vettel was leaving Red Bull at the end of 2014, it was even harder still to imagine him as a better fit for any team than Ferrari once he became a part of the team. The former four-times World Champion began his tenure at the Scuderia with signature victories at Malaysia, Hungary, and Singapore to bounce back from a winless 2014 season. The Hungarian victory in particular may have outshone most, if not all of his race wins during the title years at Red Bull. Only once at Mexico did Vettel look anything less than brilliant, and only the current strength of Mercedes kept him from more success in 2016 - he briefly led Rosberg in the standings towards the end of 2015. In 2016, Ferrari seek further steps forward in their bid to topple Mercedes, and if they do, Vettel may very well halt Hamilton's reign as champion. He'll certainly give him one hell of a fight as the two battle and ascend F1's record books together in the years to come. Grade: 9.5/10 4th: Kimi Raikkonen - Scuderia Ferrari 2007 World Champion Kimi Raikkonen nearly tripled his points total from 2014, jumped eight spots up from his Championship ranking of a year ago, and was maybe one lap away from winning in Bahrain. And yet, despite all of that improvement in a car that wasn't a rather useless lump, he was still massively outclassed by a fellow World Champion teammate. Losing out 278-150 in championship points and 3-0 in race victories, the moments of brilliance for the Iceman were outweighed by the ordinary runs and even the perplexingly bad moments like his spat with his countryman Bottas. Controversially, Raikkonen stays on at Ferrari in 2016 - and although the team believe that he's yet to show his best stuff, the reality is that Raikkonen, now in his late 30s with an injury history and an attitude seemingly as apathetic as a neglectful university student, may be in for a steeper decline. Kimi's supporters the world over have to hope that's not the case. Grade: 7/10 5th: Valtteri Bottas - Williams Martini Racing For Valtteri Bottas, a step back in 2015 was still a marvelous season for a lot of other drivers. He scored only two podiums (Canada and Russia) compared to six a year ago, and never looked as close to winning a race as he did in 2014, but "Hashtag" Bottas was still a force of metronomic consistency. His only DNFs came as a result of being punted off by Raikkonen at Sochi, and an early mechanical failure in Austin. Aside from that and a handful of bogey races for Williams - plus a back injury that shelved him on the morning of the Australian GP - Bottas still consistently scored points and led Williams to their first consecutive top three seasons in the WCC since the BMW years. With Raikkonen comparatively faltering given the circumstances, he's emerged as Formula 1's new Head Finn in Charge, and will be a major part of Williams' fight back in 2016. Grade: 8/10 6th: Felipe Massa - Williams Martini Racing Rumours of Felipe Massa's demise have proven to be utterly wrong during the Brazilian's stint at Williams. The rejuvenated veteran once again graced the Formula 1 podium at the high-speed circuits at Spielberg, and at Monza for the second year since leaving his long-term home at Ferrari. On the whole though, while Massa enjoyed much better fortune than he did a year ago, like Bottas he too stepped back a bit from the form that saw him take pole in Austria and second place in Abu Dhabi, and was still outshone by the Finn. Still, he'll enter 2016 off the back of a season where he still feels rejuvenated - and may have a chance to wind down his Formula 1 career closer to the top than many had envisioned during his worst slumps a few years back. Grade: 7.5/10 7th: Daniil Kvyat - Infiniti Red Bull Racing As they were when he got his first F1 gig at Toro Rosso, the critics were quick to question if Daniil Kvyat had what it took to represent the Red Bull senior team in place of the departing Vettel. Kvyat did little to dissolve that skepticism with just five points in his first five GPs with the team. Then he finished fourth in Monaco, ahead of three-times GP winner Ricciardo, and the Russian Rocket's year really got rolling with a career-best second place finish in Hungary, followed by top five finishes in Belgium, Mexico, and at home in Russia. Given his age (he's still just 21) and the great reputation of his teammate, that Kvyat was able to just edge Ricciardo on points by three markers is a bloody fine accomplishment. It won't be long until the Russian national anthem finally rings out at the podium ceremonies in honor of Kvyat's maiden victories - he's that good. Grade: 8/10 8th: Daniel Ricciardo - Infiniti Red Bull Racing The only man to beat the mighty Mercedes team a year ago was ultimately kept off the top step in 2015. Ricciardo, who so often dazzled with his signature last-laps passes for the win in 2014, found himself the frequent victim of Red Bull's frequent lack of pace and reliability with Renault. Despite that, Ricciardo opened the year on a six-race scoring streak, and he was the only driver who wasn't with Ferrari or Mercedes to score a fastest lap of a race - Ricciardo had three of them, in fact. He had a chance to win at Singapore, but safety car interruptions ruined their strategy and their chance to take the fight to Vettel - and second place was the closest Ricciardo got to winning in 2015. The hope is that the new Tag Heuer/Ilmor/"I Can't Believe It's Not Renault" power units can give the ever-grinning Aussie the race-winning equipment he deserves in 2016 - because when he shines bright, F1 tends to shine as a whole. Grade: 8/10 9th: Sergio Perez - Sahara Force India F1 Team In his second year as teammate to Nico Hulkenberg at Force India, it was Sergio Perez who scored highest of the two. The re-worked VJM08 came into its own in the second half of 2015, and Perez, who was pounding and scratching on the door of a first Formula 1 victory on at least two occasions in 2012, seized the initiative in leading Force India to fifth place in the Constructors' championship. 63 of Perez's career-best 78 points came after the summer break, thanks to fifth-place finishes in Belgium, the United States, and Abu Dhabi, and his signature drive to the podium in Russia. He did this as his much higher-rated teammate seemed to fall just short in the same stretch of the season. Perez won't turn 26 until January, and this year, he proved to be more than just an opportunist or a flash in a pan, but a true racing driver who's rounding out before our very eyes. Grade: 8.5/10 10th: Nico Hulkenberg - Sahara Force India F1 Team That's Le Mans 24 Hours champion Nico Hulkenberg, thank you very much. Hulkenberg's victory at the great race for Porsche was the high point of a year in racing that otherwise wasn't up to par with his past benchmarks. The edge he had over Perez in qualifying results wasn't as decisive as last season, and while it didn't help that Force India were struggling early in the year, a trio of sixth-place finishes as a season best for Hulkenberg does not match the sterling reputation that he's built in his still-young career - especially as Perez began to shine late in the year. Luckily, he's still got two years on his deal with Force India to fight back, and value-for-money, he's still one of the sport's most productive drivers. But the rapid man from the Rhine, who is nearing 100 Grands Prix without a single podium finish, is starting to plateau just enough to cause some concern. Grade: 7.5/10 A Final Commentary Another year of Mercedes domination and a drought of classic races compared to the year before would make for an unenjoyable season for most. Look beyond just the overwhelming power of the Silver Arrows, however, for the moments that made F1 enjoyable in 2015. An underdog team that was given no hope to even race again not only did just that, they went the distance and might have an even brighter future ahead of them - whatever form Manor takes next year. In a down year for the Red Bull racing dynasty, their young drivers overachieved where their machines let them down - and perhaps it was the Toro Rosso "junior team" and its rookie duo of Verstappen and Sainz that had the better performances. Romain Grosjean gave Lotus one last great triumph in Spa, as he leaves for a new beginning and the team itself reverts to Renault. Force India climbed to unseen heights since their days as Eddie Jordan's Buzzin' Hornets, thanks to the stellar drives of Le Mans winner Hulkenberg, and Perez, who two years ago may have found himself in risk of being out of F1 for good. And fittingly, Ferrari were back on their winning form, and Sebastian Vettel, once subject to derisive and tasteless jeering after every other victory in Red Bull blue, became a people's champion in the Rosso Corsa of Ferrari, setting the stage for what could be a monumental tilt for the World Championship in 2016 as he fights Hamilton and Rosberg for the title. Sadly, this year was also a cruel and unforgiving reminder of the dangers of motorsport. Jules Bianchi's memory will live on in the many years to come, after his fight for life ended in July. And that Justin Wilson, whose tenure in F1 a decade ago was far too brief for a man of his talents, was taken so soon afterwards, only deepens the sense of cruelty. Formula 1 is only one of many motorsport series that must stay proactive to ensure that these tragedies are fewer and further between. -R.J.