Yes, the depreciation situation on the Thielert-engined Diamonds is quite suprisingly "not bad", now that Thielert are again shipping parts.
However, one should not completely disregard the possibility of Diamond itself getting into financial trouble. The whole GA business is in dire straits, Diamond are extending themselves financially on a number of fronts (they seem to have resumed development of the D-Jet, after reportedly shelving it 6-12 months ago, and they spent a load of $$$ getting the paperwork for the Austro engine signed off) and they have now bet the whole shop on the Austro engine being reliable.
Their only hedge against this utter disaster is their old business which must still be generating some cash, and the very rapid move they did to get an avgas DA42 certified for the US market.
If the Austro engine causes problems, Diamond will be in severe difficulties and the Austro engined owners will be in an even deeper water. With Thielert, there were able to rely (with any non-private buyers) on separate contracts for airframe and engine but with Austro they won't be able to do that. I don't know whether there will be a certified downgrade from Austro to Thielert (for a from-new Austro engined airframe) but can you imagine facing such an option? A bankrupt airframe maker, and you have to chuck away a worthless engine and install an engine with a known poor reliability record made by a firm operated by an Administrator
