Which helmet is best

try them all on. they fit different head shapes, so pick the one that fits you properly. there is a substantial difference between head shapes and fit.

The Corsair is the real deal if it fits you well, its light, snug, quiet and well vented

I have the all new Profile and it fits my "long oval" head perfectly. It is light weight, vents relly well in hot weather, and seems well constructed. The only downside is a lot of "booming" wind noise from around the bottom opening of the helmet.

Cheers.

i posted this acticle up for the scorpion exo 700 vs 400 thread, but it applys to all helmets. i think that it is very interesting, and informative. a good read whether buying a new lid or not. it is a bit long though.
http://www.motorcyclistonline.com/gearbox/motorcycle_helmet_review/