Well I happen to also have, and shoot with, a MF SLR, in my case a Mamiya 645 Pro with the AE prism and winder grip.
Pros relative to my Yashicamat for the 645 Pro:
Correct image viewing.
More shots per roll
Faster and easier film loading - both swapping backs (very fast and easy) and loading the inserts (somewhat easier than the Yashica though YMMV as this is subjective. Loading the Yashica is certainly not difficult but does take a minute.)
Interchangeable lenses of excellent quality
Mid roll film changes area easy with the backs
Polaroid back for proofing
Closer focusing with no parallax. I don't find parallax a problem with the Yashicamat but mainly because it just doesn't focus close enough.
Cons relative to the Yashica:
Smaller image area, if you print the 6x6 negatives full frame - same if you crop them to same proportions though
Much more expensive - I paid $450 for the 645 Pro, AE Prism, winder grip and 80mm 2.8N lens, which was a fair price in excellent condition. I paid $185 for the TLR. Then I had more lenses and backs and inserts to buy.
Bottom line is that the 645 is more versatile, of course, but I actually enjoy walking around and shooting with the Yashicamat more. It's unobtrusive, gets lots of smiles and favorable comments, is very quiet, and unlike the 645 Pro I never feel like I have a cinder block, or an albatross, around my neck.
Last edited by Roger Cole; 05-11-2013 at 11:52 PM. Click to view previous post history.