JUST-local:
G-AB has proven to be a very reliable and effective aeroplane and, after a few teething problems (mostly water ingress into the ECUs), went on to do 1050 hours in a little over two years. It has proven to be nice to fly and has a much better CPL/IR pass rate than the Seneca that preceded it.
When Thielert ran into trouble mid-2008, this was at just about the worst possible time because the engines were approaching 1000 hours and were therefore due for replacement - but Thielert were no longer honouring the warranty! There was the choice of spending a lot of money on new Thielerts without any warranty at all (at that time) or parking the aeroplane and waiting for the new Austro Diesel to become available and leasing in replacement DA42s to ensure that training could continue.
A "strategic" decision was made, and the aeroplane was parked up whilst Diamond developed and certified the AE300 - although that did take longer than anticipated.
Diamond have been very co-operative with financing etc., by the way, and appear to have realised that although they were not to blame for the Thielert collapse, they did need to work to minimise the fallout.
If the promises for the AE300 come true then it will be a much more reliable and economical engine than the Thielert. If my memory serves correctly, the cost of parts used during scheduled maintenance should be about 90% lower than for a Thielert.