645 or Sq Medium format

[bnstein]

If you luuurve the square dont go past it.

If its neither here nor there then its a tougher call: a *little* size and weight less, some faster lenses versus built in shift as David has demonstrated versus some who pretty much never print square. Both are very fine cameras so dont sweat that side of it.

[jordanstarr]

...why hasn't anyone suggested to get a 6x6 camera with a 6x4.5 back? For the Bronica SQ-A, you can get the 120J or 220J backs which are 6x4.5 and you can use the regular 6x6 backs as well. For the Hasselblad you can get the a-16 backs which shoot 6x4.5 and have some a-12 6x6 backs as well. It's the best of both worlds and you don't have to be concerned with two different systems.
I agree with a previous comment though when it was said why is the 6x9, 6x7 formats not considered? You can get a Mamiya RZ67 and you can have backs for 6x7, 6x6 and 6x4.5, which would seriously help you expand your formats.
You can also just get a 4x5 camera with a 6x12 sinar rollfilm back which will adjust to any size you want between 6x4.5 and 6x12.

...jordan