In my opinion there is less felt recoil with the C models but I normally do not recommend them for defensive use. If you fire it too close to your body, you could burn yourself. I have seen them fired at night and I do not feel that the flash has an affect on night vision or anything like that, my main concern is the danger of burns.
If you plan to use the gun for nothing other than range shooting, the C model would be fine. If you plan to carry it, however, I suggest the "regular" model.