I purchased MW3 on the week of release and despite being very tempted by BF3 the beta didn't tempt me sufficiently to purchase. If you are happily playing MW3 (and lets face it millions are) then please carry on - and enjoy. If on the other hand you are reading this then chances are, like me, you are becoming bored of MW offering little new at each instalment.
I didn't really want to review MW here but am finding it almost impossible to write a review without comparison.
The main reasons I have given up on MW are that the maps have become rat runs and there is almost no teamwork or any benefit to teamwork. This is where Battlefield takes over, the maps are enormous and it encourages your team to act exactly as a team. The addition of vehicles and a destructible environment significantly add to the enjoyment.
I have only ranked up a couple of times so far but there is a huge amount of potential for this game and I am enjoying it far more that MW3.
This is not the perfect game however. The buttons cannot be set up as per COD, the weapons set up is cumbersome and far from user friendly. The weapons aiming is taking some getting used to and there is a significant amount of recoil (then perhaps that's down to my lack of experience) Graphically it's not fantastic and on the PS at least MW looks better.
I would love to see the best of BF and the best of MW merged into one game but that is just not going to happen. I will update in another month but for the time being I'm going to conclude that for its faults this beats MW 3 by a mile.
EDIT 2 weeks on. I have not played MW once since i started BF. Nor have i been tempted to. It has taken me some getting used to. This game is very different to MW and i have had to learn all about FPS all over again. Apply MW tactics here and you will not do well. I have found both the jets and helicopters very challenging to fly and getting time piloting both is rare, so my skills are improving very, very slowly.
To conclude though MW the king of shooters is dead. Battlefield has taken the crown - and rightly so. It is better than MW in almost every single way and i am looking forward to spending many hours here.