UC2 is *fantastic*. Whether or not it should have had the 'Unreal' title is debatable, since it veers so far from the other games in some ways, but it's a fantastic game. It could have been better (some of the maps aren't great, it has too few user definable options, and two of the game modes aren't too enjoyable, etc) but it's still a great game, even today, and I play it every so often.
The game performs terribly, with low framerates and a lot of other general stutter too.
To you, maybe, but to me it's fine. Maybe you're just used to a fast PC, and newer consoles, where a frame-rate would walk all over UC2's frame-rate, but to call it terrible is a huge exaggeration. Otherwise the game wouldn't have been so popular, would it? If you want to see worse frame-rates than UC2, look at first person shooters on the N64, for example. But even there they are perfectly playable.
I think it's the same CPU bottleneck you see in the rest of the UE2.X Unreal games when you start piling on the bots, only it's 100x more apparent on the crippleware console.
Why insult a machine that others love? Personally, I play (and love) PC *and* console games, and don't feel the need to criticise either. Some people still love the Atari 2600 (and there are even new games being written for it by fans), but I wouldn't play on it, and don't see the attraction of the machine, but I wouldn't belittle it. I don't feel the need to either criticise other people's choice of gaming platform, or to boost my own ego by bigging up my games machines.
UC2 saw the xbox over-extended beyond it's limits, they should have released it as a launch title for the 360 instead. This might have also helped it get the attention it deserved, instead of becoming one of the most underrated console games in existence.
No, it was fine on the XBox. True, it would have made a great XBox 360 game too, but if they'd changed nothing else, then it would have been the same game, with just a faster frame-rate and a higher resolution, and would not have played any better (or worse) than on the original XBox.
I do really wish it had come out on the PC, though, as (a) I think every good game should be available to all gamers, and (b) on the PC it would have received some fantastic stuff from the modding community.