2/ Thinking of the future. The PS3 and XBox360 are dead, the next generation consoles will take over for F1 2015 , which is due out in the spring of 2015. It will be on the XBox One, PS4, and PC. The common denominator between this game F1 2014, and the next game F1 2015, is the PC. No console upgrade required.
Side note - PC versions are always cheaper than any of the consoles (for just about any game)
I have played all the F1 series on Xbox360 I don't know what multiplayer is like on other platforms, but it has been excellent in my experience on the Xbox360, no trouble finding a lobby and a speedy transition to a race. The only times I have seen a problem is if an individual has serious connection lag. It's rare, but it usually occurs when you are in the garage after the clock has finished counting down. It's easy to spot so you can exit early. I stuck it out once and had an easy solitary race and obviously a win. But all in all I have found Xbox multiplayer very slick.
I am also wondering whether to get an Xbox 1 or new PC, which I need anyway for the latest RTS games. But it's the steam aspect of multiplayer that concerns me. How long to connect to a race, how problematic is it? I played a lot of Red Orchestra on steam, great game. However, quite often when you clicked to join a lobby it would trigger either a mod or map mod download and these could take a lot of time. And I couldn't tell which were mod or map update lobbies even though I used the filter. Even with the filter, I still got lengthy downloads - lengthy because steam is well.... sloooooowwww.
Steam has nothing to do with multiplayer on PC, at least not in the way you think it does. Steam is essentially a DRM check for this game.
On the PC it's the same stupid peer to peer lobby system as a console. You start the server, so you are the host.
Your multiplayer problems with Red Orchestra and mods/maps/downloads are through dedicated servers. With dedicated servers the admin can load whatever content that's allowed, and configure the game to how he wants it to run it. Much like our Race Department racing servers.
It is precisely because the Codemasters F1 games don't use dedicated servers, that makes the game such a piss-poor platform for multiplayer and competition in general. There is very little control, and the network quality is only as good as the host's connection. Dedicated servers are hosted on high quality hardware and have tons of bandwidth.
Quality of racing? Well personally I would never join a random open public server (whatever the platform), they are mostly full of griefers, rammers, and 3 lap sprint races.