Its good but varies on servers.
Personally the maps are too small for 32 players and more, and the game is miles better on 'Hardcore' servers where you get no crosshair and you die pretty easily.
I got to rank 55 pretty easily, just earned myself a Golden Ak-47 a couple of weeks ago, that took some doing (150 headshots will all the assault weapons).
There are annoyances online though, such as nooby unlocks/perk, like grenade spam, and the ability to drop a live grenade when you die.