Timothy Blum wrote a review of Castelli Sorpasso Bib Tights on August 9, 2011
I bought these mostly for the chamois, the X2 being the top of Castelli's line, and that they're from the Rossa Corsa line which has the best aero fit. I bought XL at 6'2" 185lbs and they are just a tad short at the ankles but not bad. The straps are a nice medium width elastic with no seams and grippy underside. One small gripe is that the backside of the zipper pull at the bottom can dig into the ankle if you don't put your longer socks on/underneath the tights, especially if you have them a bit twisted and the zipper is more in the back of the leg (it kind of gnashes a bit on the achilles as you pedal). The tights themselves are more of a fall/early winter or early spring model as they don't have any wind protection or substantial insulation. Temperature is pretty subjective as it depends a lot on personal preference, wind, how fast you are going, etc. but these are definitely not going to keep your legs warm going 20mph in 0F weather even with no other wind. For the low temps and top Castelli Rossa Corsa brand you have to go with the Fulmine Bib Tight which I don't think they make anymore, at least not imported to the US. I have one pair of those and they are very nice tights as well. The Castelli's are on par with DeMarchi's that I also have (Contour Plus Ultra) and a step below Assos (any of the LL) which are the tops in just about anything clothes-wise in cycling.