Unfortunately my only experience was *not* good. I had a Lyngdorf tdai-3400 for some time and turning on room perfect kind of made me sick to my stomach... the music sounded "blended" for lack of a better term. Definitely less natural than without. I had the amp for about 6 months, so I knew it well and had obviously done RP setup many, many times. Just couldn't get it to sound right with my Coincident PREs. Every time I turned off any form of digital processing it got better actually, but never quite right.
Very curious to hear about your experience and add another data point.