Same as anything else if is not maintained to the manufactures schedule then you will get problems
Not quite. In this case if it
is maintained to the manufactures schedule then you will still get problems.
Ask the pilots who landed in a field in Essex not long ago (a friend had flown that aircraft). Or the club that is trying to sue Diamond for the down time on the aircraft. Or the FTO that has one Twinstar that has a rough running engine about once a week (a friend of mine is a controller, and she tries to hand over every time she sees it coming onto her frequency, as she knows a local standby is a fairly likely prospect) so always uses the other for IR tests, until that is in scheduled maintenance. Another friend of mine had to bring engineers out to where he was testing. Does nothing for the nerves.
Engines have been replaced after 300 hours, well short of even the current 1000-hour TBO. Pitch control units fail due to gearbox metal in the oil. Why are gearboxes putting chips in the oil, and why then is there no chip detector? Why did the 172 I flew with that engine have the engine just stop (fortunately on the taxiway, and I was not in it)? Are the tales that I heard true, that the DA-40/42 have smaller radiator and oil cooler than the C172/PA-28 fit, and that it is not enough?
Remember downtime is a cost, even for a private pilot. It is time when your money is invested in a toy you can't play with.
You dont get that with a Lycoming or Continental
The reason that the rebuilt Continentals I fly don't have such warranty terms is that they don't
have a gearbox or FADEC. They need neither. However they are generally pretty reliable, and usually give good warning of problems while still providing most of their power. The bits they do have are under solid warranty. The last rebuild we had done was at TBO+20%, the maximum. The previous pair were at 9 hours short, due to a minor magneto issue that wasn't worth repairing for 9 hours flying.
Anyway, chatting with my friend the former DA-40 instructor about this issue, he said that the guarantee was 2000 hours, not 2400. Can't say myself, but I'd check if I were you. And you have to pay pro-rata for the hours flown so far, so you can't just buy an engine and forget costs above the maintenance.
I accept that petrol engines also fail at low hours, or have problems. I had such an issue recently, and know of another that was very low time when it failed. But both of these turned out to be defects in remanufacture, fortunately rectified with no serious harm done. DA40s and 42s are having engine problems in perfectly correctly-manufactured engines!