From all that I can tell, there is not much between the systems ......
But, on a purchase of this scale, I went with a dealer. It is proving a very wise decision. MFDB's are complex beasts. The software is a big part of the flow, and I had to give up my Adobe Lightroom as my raw converter. Looked at C1, and it's a great bit of code.
As for value to dollar, I put up with a Mamiya ZD back for almost a year before I could tolerate it no more, but it sold me on the advantages of MFDB over FF SLR, shot the ZD vs and Nikon D3X, and the difference was very noticeable. In favor of MFDB. Succumbed to a P30+ when I had the extra cash AND the knowledge that MFDB in the studio would give me the warm fuzzy feeling that I needed to spend used sports car money on a camera.
Would you really rather have a hot Mazda or newer Harley? How about a month long photo safari for two in Kenya? That's the decision making process for a hobby shooter like me.
If you are a landscape shooter, I would strongly suggest dropping about 1K on a LF kit and shoot a bit of film, look to have it drum scanned, and that will give you a really good idea of the process.
If you are a studio shooter, Pickup an Mamiya AFD for a few hundred bucks, shoot some film, and have it scanned. The shooting process is almost identical, and shooting a good B&W film, the results are darn close, the convenience factor is way different.
Check the classifieds for Precision camera, they have a new scanning service.
Hope it works out!
and Abandon all hope if you do jump
Dave