When I became interested in the CFV-50c a few months ago, I found information and sample images to be depressingly sparse. A couple of YouTube videos (Matt Day, Matt Grainger, and a nice infomercial by Charlie Waite), a spare handful of forum threads here and over at GETDPI, and a very few images. The CFV-50c has been mentioned lots because of its price point, but there has been an unfortunate dearth of anything more meaningful - hard information by those actually using it.
All that said, I pulled the trigger on the back about three weeks ago. First impressions, used with a 500C/M, are very, very positive. Alas, I don't have either the 250 Superachromat or 350 Tessar lenses, so can't help you there. But I've been generally impressed with the imagery from shorter, classic Zeiss glass. My 50 Distagon, 80 Planar, and 150 Sonnar (the latter two the older 'C-type' lenses) all produce excellent results.
I mostly shoot Leica M with (mostly) modern glass, so that's my frame of reference. The Zeiss optics on a V-system aren't as "pure" as, say, a Summicron 50 APO. But then not much is. If I had to describe the look, I'd say they render very cleanly, but with a touch of character; with the added benefit - the only benefit - that the crop eliminates any problems in the corners.
The sensor crop tends to move your use cases to the left - to shorter nominal focal lengths. I am using the 50 much more with the MFDB, whereas I use the 80 more with film. Your 250 and 350 glass would be crazy long with a MFDB. Heck, they're crazy long on film! ;-)
I'll probably write up something more comprehensive on the CFV-50c in a few weeks. In the meantime, I highly recommend it for those wanting very high quality digital files from V-system gear.
