Interesting topic since I'm debating what to replace my Mamiya 645 with. I've had my eye on a GS1 and SQAi but have been wanting to ask someone a fairly dopey question and this looks like a good place! (I don't know anything about these cameras) Do these cameras have instant return mirrors? How does the leaf shutter work in relation to the viewfinder, mirror and exposure? I'm used to my Mamiya acting like a clunky SLR and want a camera with the same 'convienience' I think I want a bigger neg than 645 based on the 6x9 negs that I've been getting from using a Box Brownie I'd probably be considering a Mamiya 645 Pro (whatever the interchangeable back one is) but they are rare here and always advertised for premium prices (not sure if they actually sell for those though). The Bronica's are much more affordable. I could swing a Hassy with std and small tele lenses but the moment you want to go wide the prices sky rocket!