I'd say it's worth it, but only if you have somebody else you can play it with. It's really one of those games that's not nearly as fun by yourself, not to mention it'd be very time-consumingly difficult to beat the Single Player on your own. Also, it'd probably be wise to wait a few weeks before buying it, to see if any patches are released for it. I've noticed lots of glitches in the Terrorist Hunt missions, mainly to do with when the terrorists spawn. Like, you could clear the entire level, but still have twenty left to kill. So you'll go running along then get shot from a room you've already emptied; it's very frustrating.
But those things aside, I'd say it's certainly worth purchasing. The controls are pretty smooth, the graphics are good, and the levels are pretty awesome.
