[Bullitt]

Absolutely you do. Destructible environments/buildings, loads of fun vehicles to drive (jeeps, boats, tanks, jets, helicopters, APCs), 4 different very customizable classes that work towards team-based play, 64v64 gameplay on huge maps or down to 12v12 if you want small group games, best graphics engine out there powering the game for stunning visuals, and every little detail you can imagine like the sound of bits of rubble raining down around you, from that tank shell that just blew open a wall across the street from you.

Oh yeah, MW3 has none of the above. Hands down BF3 is the way to go.
And yes each platform is only able to play within that platform. No PC to xbox, etc.