These are really comfy bibs! Very comfy straps, nice pad. I do have a couple of suggested modifications:
1) fit is really snug, even in the Medium. I ride Castelli team clothing and am a typical lean Cat 1, and their stuff always fits in a medium well for me. Even with a 29-inch waist, the Sorpassos run smaller than most Castelli stuff. Legs are tight if you have sprinter's legs, probably OK if you are built like a typical GC guy. Size up accordingly. I can wear the Medium, but it is borderline, and the large would probably be just fine. Since I wear Medium in about 10 other pieces from Castelli, this is a little annoying. They need to stick to their game-plan with regards to sizing. My Fondo bibs, also in a medium, fit a good size larger in comparison; they are a true medium, these are close to a small.
2) the weave of these bibs is supposed to be tighter and lighter than normal bibs. It would be cool (actually warmer) if they made the bibs a little heavier weight. They are not quite true winter bibs: under the high 30's, your legs are going to get cold; they run cooler than my Giordana and Pearl stuff. I know they make the Polare for a cooler bib, but it has windstopper material that doesn't stretch and fit as well as these do. It would be nice if they beefed up the Sorpasso for real winter conditions (say warm enough down to high 20's) as they have plenty of other bibs (like the Fondo) that are also in this temp range. Because of this, the knickers may be a better bet. I usually only run bibs when the temps are going to be sub 40 for the entire ride; you can run tall socks with knickers and get good coverage, then pull them down if it heats up later in the day.
As far as performance goes, and comfort, these are first rate. Just watch the sizing and keep in mind they aren't toasty warm.