This is the best shooter ever made, way better than MW2.
Though even in Call of Duty 4's greatness it still has it's flaws. For one the servers suck, even on xbox who claims to have the best servers. It is unbearable how bad the lag can be, sometimes it will take a magazine to kill a foe. A lot of the time a single laggy "one bar kid" will ruin the entire game, resulting in me dashboarding due to a bad kill/death ratio. Beyond that it is pathetic how you will continuously rejoin a game that you just quit, even though the score is 700-200. Also in game the spawns suck, often resulting in frequent spawn-kills.
Also the perk system is pointless as all anyone uses is stopping power, and juggernaut is donned a "noob perk". Many other perks are unbearable such as steady aim, martydom, and last stand, which reward you for being a noob.
Even with these flaws i'm not done yet. Many of the guns are unbelievably overpowered such as the M16, RPD, and MP5n, though primarily the m16, as it will kill you in one three round burst across the map (in the leg haha). It also has no recoil and extremely high accuracy (no skill). Not to mention you can kill an entire team with just one magazine using it.
Beyond this many of the maps are good and do not encourage camping (unlike its garbage sequel mw2) and overall this game is excellent. Do not let my complaining tell you otherwise, I recommend it to everyone, do not buy mw2, this game it is sooo much better. Its just a shame that its developer, Infinity ward, decided not to improve the online play but make it much worse. (BTW i gave mw2 a 3/10 on this website).