Great game if played lightly, just don't overdo it.
The Good:
Its free. Everything, its just... free. That being said it is a pretty good game to not cost money. The guns sound similar, but great. And while there isn't an RPG amount of weapons and items in this game, you won't ever come across a useless weapon. The map designs are a descent size but seem bigger because of the many routes and sniping positions to find. The maps also are not only original, but look good while being original. The online players provide a descent challenge and won't troll or purposely bother anyone. The gameplay is what you would expect, a basic FPS. Still, I wouldn't try run-n-gunning in this game, because you die in a few hits to keep it realistic. Find a good vantage point and try to not get noticed by the other players.
The Bad:
There are about as many bad points as there are good. The graphics aren't that impressive, but that is considerable seeing as this is a free online game. That being said, the animation isn't that great, and it IS noticeable enough to complain about. The game has a number of glitches, while not very often game breaking, they just get annoying. Another bad thing is that you can only rent weapons, but you can't keep them. It also seems like they have a hard time keeping the servers up, because the servers have been down for 3 days straight on my end. This game is also only available in the U.S., take it for what you will.
Overall, its a great game to kill time, its free, and fun. Just make sure you don't play it too much or it could get dull faster than it really should.