Since not many responses, I share my brief experience:
I've test driven one with the carbon buckets, it was very short drive but based on that I'd say it's much safer to not buy them unless you get to test them. I'm quite a small guy and they felt great for that short test drive but they left me thinking how I'd get along with them on a longer trip. One notable thing is that you can't adjust the tilt angle of the bottom seat part, so it either fits you or not. It's close to my seat adjusts but might be too steep for somebody.