@confuse_upgradeitis - I used a crown xls1500 for about two years. This past winter I bought a used pair of Ghent audio class D monoblocks here on Audiogon. I was sceptical, since their power ratings were the same, but I was getting too curious about what, if anything, would sound different from my crown.
What I’ve heard is an improvement in clarity, sound source separation, a reduction in harshness and an increase in bass clarity and smoothness. In addition, the sound stage is deeper and wider.
Now, all of these differences took a few days, maybe a week, to discern. So, while it was a significant improvement, it wasn’t a quantum leap and I still greatly respect what the crown brought to my system for $325 brand stinking new.
I did, however, go from a stereo amp to monos, so I can’t speak as to what improvements were due to a better amp and what were due to moving to monos.