This past December, after using the Canon 5D for a year, I took the plunge and bought a Contax 645 with a refurbished P25 back. As I am shooting only personal work, my decision had nothing to do with client requirements, but more to do with film support services disappearing. I also did this because I am printing 24 wide inch prints in my studio and I wanted the extended resolving power of the MF format. I have not had one issue mentioned by Henry with my back. It has worked seamlessly on the Contax 645 without lockups, excessive noise or any other issues. Also, this is not a closed system, I could use a Leaf or Kodak back as well. As far as customer support goes, I have nothing but good experience to report with both Lance Shad from Phase One and Zach Radel from Digital Transitions (the vendor). I have called customer support on a number of occassions and have encountered only competance and courtesy, not arrogance or indifference. This is my firsthand experience. I hope this reassures you.
