Moved from Luxman 509z integrated to m900... Wait for it.. the difference is quite noticeable. It is bolder, more detailed, more bass even at low volume listening.
Sound is more fuller and robust. Great part is that I am driving this directly from dCS Rossini DAC, directly in without even getting it warm.. lol . .. so once pre amp is introduced there might be more upgrade..
M900 is amazing specially used .. no brainier at ~$7k