So I picked up MW3 on Tuesday.
So far I've played through Act I of the campaign and put in about 3 hours on multiplayer.
If you're looking for innovative new features, don't get your hopes up. Its basically new maps, similar weapons, and a couple new perks in multiplayer as well as new ways to achieve in-game perks like air drops and counter-UAVs. The campaign is just a continuation of the same story line (something with russians and 3rd-world people, blah blah blah) and some new cinematic cut scenes. Game play is the same as every other MW title.
Don't get me wrong, its still awesome. Just not any awesome-er than, say, MW2.
Anyone else got play yet?