I'm 6'3", 205 pounds, I wear a large Pearl Izumi and just about everything else in bike clothes, BUT, my Assos bibs are XL and I just squeeze into them. They specifically state that they cater to athletically trim people and in the biking world that means pro weight, which is substantially lighter than the general fairly fit individual. So, be warned, and be prepared to send it back if it does not fit.
Having said that, and believing they are grossly overpriced, I really do like the way they feel.