Krell iBias Amp Dependability: An Informal Survey

The Krell Duo 300 XD has been the biggest, brightest jewel in my audio crown for the past three years. What it does (when it does it), it does it superbly. But I'm about to send the unit back to them for the third time due to maintenance issues. The latest problem is a power supply failure, which is different than the previous two issues which both had to do with the amp overheating. I'm wondering if it's just this particular copy, this particular model or if there are broader quality control issues going on with Krell's latest generation of iBias amplifiers that others here are also struggling with. I'd prefer this not turn into a "let's all rag on Krell" forum just for the sake of venting. Rather, I'd like to learn whether this is a common issue that, to my knowledge, has yet to be discussed on this forum or if this truly is just a bad apple that I had the misfortune to buy. If anyone else has experienced repeat problems with their amp within the line of iBias products, please chime in. 

My system consists of:
PS Audio Digital Link III D/A converter
PS Audio NuWave phono preamp
Classé preamp
Krell Duo 300 XD (plugged into a dedicated 20 amp circuit) 
Mangepan 3.6 speakers
Nordost interconnects and speaker cables