The reasons I am thinking about 12 TC are:
1. It could be one of the smallest mechanical medium format camera. They are a bit like Leica M, small with mechanical excellence. They are those cameras you like to fondle. TC 12 is the smallest one from Alpa, the others like 12 SWA is too big for me. I don't want to play with the shift mechanism. I like the obliquity and the ''pulls" from the wide angles.
2. When I am taking photos with my wide angles, I always go for f5.6 or f8 with or without a tripod. I rarely go for f4. Most of Schneider lenses have f5.6 as the maximal aperture. With a small aperture, it is easier for Schneider to reach optical excellence. I think a small maximal aperture and a tripod are the key to get great shots in wide angles.
3. My alternative is Hassy, but all their bodies and lenses are a bit big for me to handle, so
are the items from the other manufacturers. I was thinking about the Hassy SWC Zeiss 38mm f4.5 Biogon, but I am not at all impressed with the MTF graph. Sinar Zeiss 4/40 Distagon is good, but if I go for Sinar, we come to the problem of being big again. Sinar does not have many lenses available at the moment. Sinar Zeiss 4/40 might not be wide enough for some applications.
4. I have tried handling Hassy 500 series and Contax C645. No doubt they are essential tools for Pros but I feel the shutter anounces itself too much. I have not tried an Alpa yet but I would assume it is more quiet like a rangefinder.
The lenses I am going to try are Schneider 38mm 5.6 it has an angle similar to my 21mm distagon. Makro-Symmar 5.6/80 and Makro-Symmar 5.6/120 are the other two I wish to try.