I have used an Arai Quantum for the last 12 years, bought it when I used to ride Jap bikes way too fast - it was the only full face I could find where the visor did not come up if you looked over your shoulder at 120mph.
It is quiet (maybe a little too quiet), quality (I know i did 50000 miles + wearing it in the UK, year round, much less in the SC where there is no helmet law, but must have over 70,000 miles in it by now), the vents work well, and I find it extremely comfortable.
Only downside is cost - but I consider it to have been exceptional value.