Snell refuses to certify flip-face helmets, so no flip-face helmet can ever be certified by Snell.
I've had mine for two years, and I love it. The foam lining of my prior Shoei Multitec compressed over several years, rendering it eventually too large for my head. The C3 is as snug today as it was the day I bought it at my local BMW dealer.
I ride year-round in Seattle, and the helmet simply won't fog the visor no matter how cold and how wet it gets. The integrated sun visor works brilliantly, and I'll never own another helmet without that feature. Not having to ever mess with sunglasses inside the helmet is priceless!
Despite being festooned with all these features, it's also one of the lightest helmets on the market. If you ride long days, your neck will appreciate the lighter weight at the end of the day.
I've had no issues with buffeting on either my fully-faired RTP or my minimally-faired GSA, and it's been measured by several of the m/c magazines as the quietest helmet on the market. To my knowledge, it's also the only helmet where it's quiet enough inside that earplugs become optional instead of mandatory.
When I need a new helmet, I'll be getting another C3 - unless of course Schuberth has supplanted the C3 with a new model.
As far as long-term ownership costs are concerned, I've found Schuberth customer support to be stellar. When a faceshield retention lever somehow fell out, they quickly sent me several replacement parts at no charge. If you're experiencing premature failures, I'd highly recommend contacting Schuberth North America directly for assistance.