I just went from a Shoei Neotec to a C4 with the SC1 Advanced comms system. For reference I've also had a C3 Pro and a Nolan in the recent past. I wear a large in everything, but after trying one locally, strangely I took a Med C4. I recommend trying as I had two completely different sized C3 Pro helmets, both marked Large. The C4 fits my head much better than my well broken in Neotec. Huge eyeport for great vision. That ties in with the small size of the shell. My C4 can turn completely from side to side without snagging my jacket collar at any point. Not even close to touching. Looking up, it does not touch the back pad in the jacket the way all other helmets that I've used have. In the hand, it feels no lighter than my other helmets, but in use, it feels featherweight. The pinlock is shaped along the entire faceshield, so it isn't obtrusive. Not sure that i'm ok with the loss of clarity with it in, but after one long ride, including rain, i'm not sure that i'll remove it either. I didn't think it was venting well UNTIL I felt how much rain came in the top vent with it open. There's no way that air isn't getting in as well. Next ride, i'll try without a hair/head cover. The integrated SENA system is very trick! Speakers and mic already installed. The mic is actually in the brow, in the eyeport, believe it or not. Two out of three call receivers reported their best sounding calls from me with the new helmet. One concern was the inability to recharge the SC1A while in use, however replacement batteries and USB tankbag chargers are available and will make this a non issue. Just as easy to swap batteries as to plug in a charging cable to a 20S or 30K. I used a battery for 10 hrs, recharged for 3 and used for another 8.5 hrs on my first ride, until my spare battery and charger arrives. Interestingly, the shipment is arriving from England in 2 days when it takes 3-5 days to arrive from one US state away. No boom mic to move for eating and drinking was a nice feature as well. The SC1 Advanced did have "the usual" SENA quirks that prior units I've tried have, but nothing I didn't expect. I was able to pair a GPS as mobile one, my cell to that GPS and my SM10 with radar detector as mobile 2. In all, compared to other higher end helmets, this one is worth every penny to me personally. The communication system was worth it to me only for the seamless, integrated capability. Helmet i'd give an A+ if your head shape is right. SC1 Advanced i'd give a B- for perfect integration, but mediocre to poor operation