I would be wary of viewing this as "a heck of a deal." This has the feel of a fire sale in anticipation of Sinar pulling the plug completely on its digital back business. The sale runs out on June 30, the day before the insolvency proceeding for F&H in which the affected players will presumably have to put their cards on the table with the Hy6 and put up or shut up.
Who knows what might happen to the various MF players, but as long as there is a Sinar, they will be legally obliged to honour the warranty for 3 years, and the back will still produce high quality images for years, just like any other back costing much more. Given the price and features, I would still call this a deal. Heck, you could buy two for the same price as the equivalent Phase back. The only real threat is if Sinar closes its doors altogether.