Are there any strong feelings as to why a 501CM wouldn't be a good idea for this (or any) back? I shoot people. I would say 60% natural light and 40% strobes.
I use the Hasselblad V system with a P25, mainly for architectural work alongside a Linhof M679. The V system has a few advantages,
-easy switch between vertical and horizontal format, even with a waist level finder
-a number of genuinely exceptional Zeiss lenses, like the 38mm Biogon, 40mm IF, 100mm, 180mm, 250mm superachromat, and 350mm superachromat
-1/500 flash synch
-the Hasselblad Flexbody, a light and easily portable unit giving tilt and +/- 15mm shift with most lenses and a 37mm x 49mm digital sensor
-outstanding Acu Matte focusing screens with a range of really effective focusing and framing aids
-bullet proof mechanical reliability
-huge rental inventory
But there's no such thing as a photographic free lunch, so there's a few notable drawbacks to using a digital back on a Hasselblad V camera
-the mechanical shutters are less consistent than electronic shutters, you'll sometimes see about 1/10 stop exposure difference within a series of frames
-there's no possibility of TTL flash control, so fill flash is that bit more difficult
-the cabling from the lens to the digital back is a weakness, it can sometimes come loose (and Murphy's law says that will always happen when an unrepeatable shot presents itself)
-you'll need a three way adapter to link the cabling in to studio strobes, so that means you've five or six electical connections to potentially let you down
