You can't compare the games really because they're both doing different things.
They're also both quite flawed.
BF3 has some big problems with the UI design and function (more so than Ro2), it's pretty but it's rather painful to use. The good squad management system that was in BF2/Bad Company 2 has been ripped out and shat upon from a great height.
There's also some class balance issues (Recon is near useless) and some weapon issues, some guns obviously OP while pistols generally far too weak.
Origin and Battlelog are rubbish. Oh dear god it's rubbish.
The maps unfortunately suffer from consolitus and the Rush maps in particular have objectives far too close to each other, nullifying any tactical opportunity and turning into a fragfest. I suspect the BF2 maps being added with the Return to Karkland DLC will turn out to be the best maps in the game.
Saying that though, BF3's core mechanics are actually fun, and it could be a great game with tweaks.
The thing is, I can do a somewhat similar list for Ro2 and pick faults, but for all its flaws I know TWI will at least look at them and have a crack at fixing them. Sadly I can't say the same for BF3 based on DICE's past conduct.
TL;DR: Both Ro2 and BF3 are flawed. Ro2 won't be in 6-12 months time whereas BF3 will probably always be broken. In the long term, I think RO2 will be the better game.
Edit:Whoever mentioned the graphics earlier: On my system Ro2 looks quite bad, BF3 looks much prettier although they both run about the same speed fps-wise. I suspect that's down to a business issue though, Dice being able to afford to hire experienced people to exclusively work on optimisation.
