For me, Battlefield 3 without question, but they both offer something different.
I used to really enjoy CoD4 when it first came out, so much so on release day I ended up buying two copies – one for 360 and one for PS3, as when me and a mate tried playing one (PS3 iirc) the network was down, whereas the other version’s was ok (had way too much disposable income back then!).
Anyway, it was good fun to play, the weapon unlocks added a fair amount of replay value as you worked towards unlocking them, and I have many fond memories of the game as a whole, even single player.
With the release of MW2 I felt the series lost a lot of the skill required to succeed, the kill streaks kind of ruled to roost now and players were out to unlock the biggest and best in the shortest possible time, which lead to a pretty dubious play style for some people. A lot of my enjoyment slipped away with the series, and it became less and less of an attraction.
The Battlefield games have always been close to my heart (so to speak), as it was one of the first multiplayer games I ever played – 1942 on the PC with modem dial up gaming.... awesome. Since then I’ve followed the series pretty much all the way through, with the exception of 2142 (pile of **** that was).
I find these games offer another dimension to gameplay that CoD does not – especially with the later games in the series - the addition of destructible environments was brilliant and just highlights how far behind CoD is in some ways; granted this isn’t the be all and end all, but it certainly changes the dynamics of gameplay and makes players think a lot more about their actions....
CoD reminds me of Unreal Tournament, with a different skin on and some bells and whistles, it’s just as fast and requires (at times) some pretty quick pin-point reactions to play well, whereas BF is slower, more methodical – the addition of vehicles makes you think more about your character class and working as a team is much more apparent (even with randoms).
I don’t hate the CoD games, but for this gamer, it’s Battlefield 3 all the way baby
