My helmet is a XXL and it fits the average head well. I dont think i have a large head, but the L (well in my model!) wouldnt even come close to fitting a normal blokes head. Dude at Revolution Racegear told me it's pretty common! I guess like all items we can wear, just gotta try each model on!

I got mine their, i think i paid about $150, but you can obviously get them cheaper from Tenagah etc