I have both... Low light outside, no tripod, I'd take the Mamiya, even though the slower lens is kind of a hassle; for me, it's just easier to carry around in hand and take quick shots. If you're getting into flash photography, follow what postalman says and go Hasselblad...the accessories just make it easier to use as a studio/flash system. Depends on what kind of shooting you're looking to do. (Also, if you go Hassey, just lock up the mirror, and the shutter's just as calm as the Mamiya.)