I am 6'3" 200 lbs with a 36" waist. The XL fits perfectly. The inseam length is a little short (9"), but they are Euro-shorts, I expected this. The compression is excellent keeping everything in the right place and keeping legs strong.
Now for the down side... The chamois, was initially comfortable, but after 10 miles, I began feeling it right on my sits-bones. This is not supposed to happen. Have an older pair of LG shorts, that are wearing out, that never caused this issue. I tried the PI Pro bibs, the chamois is awesome, the fit not quite as good for my height. I read all the reviews on the Castelli and I have to say that I am surprised at the feel given all the development. The Castelli's have a vicious gel insert and I think it compresses too much and is thicker than almost any other Pro-level chamois I have tried. I do find that it is more bearable in the drops than the hoods. In these shorts, it is quite possible that the bib is rotated a bit to far forward and contributes to the discomfort on the sits-bones.I stuck with these for my last 5 rides, but yesterday the pressure started almost immediately and made for a uncomfortable 2 hours in the saddle.
Update 8/17/2012- After 58 days, one of the seams let go in the back during a ride. This was not cool.. Took some serious ribbing during group ride. So now in order to keep these functional I'll have to put more time or money in to re-sew the seem. Disappointed with the quality. For near $200 this should be better. I have down graded these from 2 stars to 1 star. RC is awesome.. took the shorts back and provided a refund... Great customer service.