Although I'm buying both(probably), I have no doubt that BF3 will be head and shoulders above MW3 in terms of quality. The released BF3 gameplay alone should be enough to tell you that, let alone how poor MW3 looked in comparison. And lets not forget how pathetically similar it looked to MW2, heck most of the guns lying on the ground were like for like copies from MW2
If i wanted a re-skinned mw2, i would by mw3. Thankfully im not retarded so ill be sticking with the only series to give you that epic battle experience. Bf3 will not be the CoD killer, CoD will be the CoD killer.