I managed to snag it free with my video card while building my computer and i can truely say that the single player, while short, lacks in dull moments. The single player campaign leaves you with a number of "did that just happen" moments, and that's a compliment. It only takes about 5-6 hours to complete so it's extremely short but man, if there's ever a character that i have full respect for, Capn Price did it for me.
If you have the cash and the urge to blow it on a short single player and a multiplayer you may dink around with go for it now. otherwise keep it on your to-do list and buy it once it's in the 20 dollar bin or someones selling/trading it here. It's definately worth it if just for the single player.