I have OC's on my sunday bike and ultremos on my other bikes and for sheer ride performace the OC's can't be beaten. I was very skepical about the "rides like a tubular" but they are good (I've never ridden a tubular anyway).

However, if it turns wet then the ultremos are the better tire and I've ridden them all year round. I managed to get 3 sets free a few years ago and I've just taken my first set off and they were flat free for a good few thousand miles.

I just dont like the tread pattern of the GP4000 on the outer edge, although a friend of mine swears by them.

I'm going to try the ultremo r this summer but the "bulge" issues have me a bit worried.