The S- and EC- series Bronicas have the strangest mirror design I've ever heard of on a medium format SLR; the S mirror goes down and forward and two light traps block off the viewfinder and the mirror, and the EC has a split mirror (the two halves of which apparently have a tendency to fall out of true with one another that is very difficult to fix). The whole point of this is that lenses don't have to be as retrofocus to work. I don't have the 40, only the 50, and it's a very nice lens, very sharp, little distortion. The 75 fits down the belly of the beast and hardly protrudes at all.
The S series are also the loudest cameras I've ever heard, and I include motor driven cameras in this; I nearly dropped mine the first time I heard the shutter go and I had been warned. Subtlety is impossible. I hear the reason the split-mirror design was used in the EC- was to quiet the thing down some.
The mirror was not the only odd design feature on those cameras--I am particularly amused by the detachable focusing helicoid, the extra 58x1mm lens mount, and the incredible disintegrating ground glass spacing foam--but it was one of the more important, optically.
So now that I've told you why they're neat, here's one reason not to get them: qualified mechanics are few and far between. In all of the US, the only mechanic I know of is Frank Marshman, and he's very good and fixed mine up real nice when I discovered that my ground glass foam had disintegrated and also that the mirror assembly was sticking.
On the other hand, if you're willing to get it cleaned, you can usually figure on getting a good S2 kit for the price of a Hasselblad lens; I think my body + 75 + back was less than the cost of a Hassy back. That was about a year ago, so things may no longer be so attractive. Although with Bronica killing the SQ and ETR, it may actually be more attractive.
