Luxman 509 or McIntosh 8900

McIntosh generally sounds lush and powerful, though clarity in the highs really depends on speaker combination.

I had the Mc452 and now have the 509X and they feel they are completely opposites.  Paired with my Martin Logan 11As (which have a slight roll off in the highs) the MC452 was too warm and lost the crispness to make some instruments sounds realistic.  The 509X loses a bit of the lush body but you get a very revealing and neutral sound character with very crisp and smooth highs.  Never fatiguing (at least to me).

it all depends on the what sound you are looking for.  I haven’t heard the Polks myself, but if they tend to be on the brighter side the McIntosh may work for you.  Either way I think the 509X is probably a bit more versatile in general.

Probably too late to add but I lived with a Macintosh amp and preamp for many years, decided to finally upgrade and for various reasons went with the Luxman 590AXII and now wish I had replaced the Mac’s years ago. The Luxman is more detailed, warmer and much less fatiguing. 

I have never heard anyone who owns McIntosh say they were fatiguing sounding. If anything, they are warm sounding. 

Deadhead1000, were using direct coupled McIntosh amps?  As Stereo5 mentioned fatiguing would be the last thing I would categorize McIntosh ampa.  If anything warm and at times lacking crisp details would be my experience.