There are times I dream of somehow being able to afford a medium format digital system so I thought I'd take a serious look at how that might work, compared to what I do now. As I have a fair amount of experience using medium format film cameras and know the parameters of medium format backs, I can do this reasonably accurately without forking out the $40,000 to really test the hypothesis.
As I use a 1Ds2, size and weight won't be huge factors, my current camera already makes a brick look slim and light. The first obvious difference is I'd probably not need to stitch normal images as a little cropping could result in a square to 2:1 image while maintaining more than 20 megapixels. Dynamic range seems to be a bit better though as it's only a couple of stops at best, I'd still have to shoot multiple images for any more dynamic range than that. Depth of field becomes a significant issue in medium format cameras - there just isn't a lot of it. This would mean that even more images would have to rely on a tilted lens (but only wide angle is available unlike my Canon 90 ts-e). I could process multiple images in helicon focus but boy, we're talking big files now - don't know how well Helicon does with those, and of course Helicon is so far only 8 bit so I'm losing some of the advantages of medium format 16 bit images.
I'd lose most of my zooms - no 17-40, no 70-200. Sure they have a moderate length zoom 55-110 but that's only 2X and neither very wide or long. No such thing as a long macro lens though. Lenses are bigger so I'd be able to carry fewer of them and not being zooms, this means I would have to hope that I can fine tune framing with my feet rather than with my lens - which isn't always possible or desireable.
The shot to shot time wouldn't really bother me given the kind of work I do. One thing to consider though is that now your back pack is worth $50,000 - that sure has an impact when you think of going in for lunch or to pick up a drink, when you fly, leave things in your hotel rooms (see Michael Reichmann's recent experience in Paris). It has significance when you hold your camera 5 feet out over a waterfall to get the best possible shot. It's already an issue - it's just that much worse with medium format.
I'd lose the rapid sophisticated auto focus I currently use - even though I focus manually I rely heavily on the camera to tell me when I'm in focus and where.
I'd have to give up long lenses. Even my 70-200 would need a 350 mm. lens and anything longer is simply not practical.
Maybe I'm just as well of where I stand.
Interestingly you could apply some of the same logic to people who shoot with a digital Rebel or XXD or DXX camera from Canon or Nikon with it's fewer pixels and smaller sensor - sometimes the crop factor means that you don't need as long lenses. The camera weighs less than half and is half the size too. Batteries and chargers are smaller.