Unreal Championship 2 is *fantastic*. In some ways it's the best Unreal game ever, though it had it's fair share of bad design choices (but the good definitely vastly outweighed the bad), and it was a travesty that it was never ported to the PC. Unreal Championship 1 was just a cut down version of Unreal Tournament 2003 (or rather UT2003 was an expanded version of UC1, since I think UC1 was released before UT2003?), but UC2 was very different to UC1 (and so different to all of the UT games), as it made a lot of changes, and most of them worked very well.
For me, Unreal Championship 2 is up there with Goldeneye, Red Dead Redemption, and Perfect Dark, as console games that SHOULD HAVE been brought to the PC, as they deserved to be played by as many people as possible.