I bought one about 2 weeks ago now. I had been using an inexpensive modular that was very loud. I then purchased a Bell Revolver which was still loud, but bearable. I finally bit the bullet and bought the Qwest since I figured I'd spend that much trying "cheaper" helmets and then buying a Shoei anyway.
It's not completely quiet, but, it's better then the modulars I was wearing. I don't have another full face helmet to compare it against directly, but, it's as quiet as my old RF700 that I used to use on my old ZX10 (up till about 3 years ago).
I can now commute without ear plugs at highway speeds without ringing ears when I stop. I normally wear plugs, but, now I don't immediately stop and put them in when I realize I forgot them :-)
Venting - on a 60 degree day, I can open the top vent and I get a nice cold spot on the scalp. the chin vent, behind the fairing, doesn't seem to do much. Haven't had any warmer weather yet for more info.
Nice aside - I had stopped at the local dealer several times looking at helmets and trying on for size. That day he said - take it for a ride, you like it, buy it. At the same price I had been seeing it for mail order. That attitude pretty much had it sold before I even got on the bike.
Seeya
Mark