I'd go with BC2. It's multiplayer had character (And colour. Fucking desaturated bluefilter BF3), and the levels showed that DICE remembered focus and channeling. The players were directed towards points where conflict could occur, but not restricted in direction. BF3 manages to mangle Rush with attrocities like Operation Metro, or constant running in maps like Caspian Border. It manages to fail it in both directions-too open in parts, and entirely too closed off in others.
The jets are nothing to write home about. If you like them, and know how to use them, you're set. If you want to learn... prepare for no instructions, an incredibly steep learning curve, and having to trawl out some Flight School servers. Ew. The vehicles feel very limited on full 64 player servers, which gets incredibly annoying. And they never really utilise them in an interesting manner like Atacama Desert, or that map where the defenders start off on a small island.
BF3 makes most of the environments indestructible, and most of the time I find myself on my own, and when I have a large group of teammates, it's always a bad thing, a clusterfuck on Metro, or everyone getting trapped in a corridor on Grand Bazaar. It's tiresome I guess is what I'm pointing at. And the graphics are horrible. Technically superb, great engine, but utterly lifeless and without art direction. The colour is entirely muted, filtered desaturated muck.
The Close Quarteres content pack basically took random spawn CoD style maps and inserted them into BF3. The maps lack imagination, and they're no more fun. The latency problems many players still experience with Frostbite don't make this more fun than the competitors either.
I didn't like BC2 at first, but it grew on me, especially as I unlocked things, and now it's one of my favourites. BF3 has fatigued me, and is now a game I never play, and likely won't again.
Oh, and the singleplayers. BC2 is a cliched piece of boring stupid nonsensical crap, which is occassionally loads of fun. BF3 is boring and not fun (That jet mission actually bored me. I got bored of my entertainment meant to prevent me from getting bored. That's a terrible failure). So it loses there as well.