Man, I bought this game for $5 ages ago... Got to admit, never had a hankering to go back and play it myself, but eh, there's still about 800 people playing on a daily basis (according to Steam stats).
My favorite game of all time. Started playing on the day of the first release when it was unreal tournament mod and loved it ever since.
If you like shooters and are looking for something different get this and spend the extra little bit getting used to the features. This isn't run and gun, spray and pray baby bullshit. You have to use tactics and operate you're weapons with more care. Once you get it I'd be surprised if you didn't love it. Plus, Tripwire continually updates their games and supports mod teams so if the Eastern Theater doesn't really interest you there's the Western Theater and African Campaign that pretty full of custom content as well.
Seriously, best ing game I ever played. If nothing else, it's $5 and you're supporting a great indie developer.