I have a C220, which also allows the changing of lenses while film is in the camera. The Mamiya TLR's are good, solid workhorses, and the glass is very sharp and contrasty. They are a bit on the bulky side, but once you get used to their size it really isn't substantially different from other TLRs. And on a tripod it really shines - plus no mirror slap, a quiet leaf shutter, nice big square negative...depending on your intended use (probably it would not be the best choice for grab shots on the street - although Diane Arbus used on in the mid to late Sixties) you would not regret the purchase. You already understand the downsides of TLR versus SLR, but the upside in this case would be a less expensive trip into medium format with a camera capable of extremely high quality photos.

Joe