I put 2,500 miles on a C3 in the first 3 days I had it.
It does everything they say. It is noticeably lighter than my C2, and significantly quieter.
I also got the SRC Bluetooth collar, which works just as advertised. It synched with my iPhone in minutes and without hassle. I got 12 hours out of it playing music the whole time and with the occasional phone call.
I haven't tried to synch it to a GPS or another helmet, but I have no worries about that.
The pinlock also works well. I could see fog all around the edges of the shield one chilly morning, but the main area of the screen stayed clear.
My only real complaint is that when you plug it in to charge, it goes into standby mode. 12+ hours is fine for most "normal" rides, but not sufficient for my IronButt adventures.
Also, since the chin bar padding fits quite well, you have to watch where the boom mic ends up every time you close the helmet. That's a minor annoyance with boom mics, but isn't specific to the Schuberth.
I was able to go to a "local" shop, JC Motors
, in Irvine, CA and try on several sizes. I ended up one size larger than my C2, but with a perfect fit. To me, that was worth a ride-in to the shop.
Yes, this stuff is quite pricey, but it just plain works.