I took the plunge and bought one yesterday at the IMS show here in the Detroit area. I measure 63cm with a round profile, and the XXL fit perfectly. I've never had a helmet that fit so well all over before. It's just a little snug, but that'll break in after awhile. I'm impressed with the whole package.
15 BMW RnineT
10 Ducati 1098 Streetfighter S - "Sleipnir"
09 Kaw Versys
67 Triumph Bonneville TT Special