At present, I have a Luxman m-700u/c-700u combo and PS Audio M1200 mono/PS Audio BHK preamp combo in rotation. The PSA M1200 amps use IcePower modules with proprietary tubed input stage. These two amplifiers are a near dead heat in sound quality, just different strengths. There's no clear cut "winner." Like Erik Squire's previous post, I prefer the Luxman combo for the type of music I listen to but could easily imagine someone else making another choice.
The implementation of custom input stages using the IcePower modules is apparently important. I also have an amp that just uses the stock unmodified AS1200 module with high end Furutech wiring and connectors and it doesn't hold a candle to the performance of the PS Audio amps. There is also a difference in older IcePower modules vs. modules used in Legacy and PS Audio M1200 amps. The older modules used in many amps are decade old tech.