I've played CoD4, MW2, MW3 (personal favorite), and Black Ops. I've been considering buying this one, but I'm not too sure if I should. Considering MW3 is my favorite, would I enjoy this one or would the differences be too great for me to properly enjoy it? This is strictly a MP question.
never met someone who considered MW3 a favourite before, cant help you out much.
I will say the maps are around the same size, the pace is faster, and generally its less oriented around aerial killstreak dominace the way MW3 was. Also perks have stronger effect, with the exception of ghost being weaker this time than assassin was in MW3. weapons are somewhat the same in terms of diversity and the perk system is a little more fun to use than the stricter set up.
For the first time in gaming history, the console contest may have been decided not by games, but by DRM