Gameplay
CoD MW2 is filled with grenade cigarettes, campers, hackers, idiots, noobs, whatever, grenade launcher noobs and so on. At least that's what I recognize when I go to my friend and we play CoD MW2.
I never played Homefront.
Battlefield Bad Company 2 has a nice physics system, but it's not compatible on low-end computers too much, inspecially when you have a building infront of you and someone shoots it with a rocket launcher. However, thanks to the huge maps, recons (snipers) can indeed camp but it's not much effective as you must advance in the battlefield with every ocassion or such.
Maps
CoD MW2 maps are intended for Close Combat, snipers aren't useful on most of the maps, unless you want to be a quick scoper forgettard and kill a person 2 meters away with a sniper.
Battlefield Bad Company 2 maps are huge, thus allowing vehicles in a easy, useful and yet dangerous (good use of mines etc.) manner.
Graphics
CoD MW2 graphics aren't bad at all and they are compatible with low-end computers.
Battlefield Bad Company 2 has a better engine which supports better graphics, but they are not compatibile with low-end computers.
Grenades
On CoD MW2 grenades are a serious problem, listed on "Gameplay".
On Battlefield however, grenades aren't much useful, usually used to take down parts (or entire) buildings, same case as C4.
DLC
While CoD MW2 has a DLC to include newer maps, Battlefield Bad Company 2 has a DLC (Vietnam) to include a bunch of new vehicles, maps, weapons, players and a new style of gameplay.
With this I will now leave the forums for today as it's late here... a bit too late...