I never played it and the responses from folks whom have is pretty polarizing ("It sucks!" "It's good!"), so I was kind of hesitant to try it. But - hey! - with discounts and all, I was able to pick up a copy from work for about $9 and I couldn't pass it up. Plus, I need something to play besides Omega 5 and Puzzle Quest while I wait for Lost Oddysey.
To my surprise, it's pretty good. Don't get me wrong, it's definitely flawed - the engine seems dated now, lack of destructible environments for something that makes you constantly utilize your surroundings, poor level design (certain doors unlock and some don't, despite the fact that they'll look EXACTLY the same), etc. It definitely feels like a game rushed out the door for launch. But the music and the atmosphere thus far is pretty immersive and it feels like it's trying for something fresh.
I totally dig it. Especially for $9. The sequel is out soon and apparently retailing for $10 cheaper than your standard Xbox 360 new release. Might have to give it a shot.