I totally agree. I had the S1000 (smallest) model for over a year running my Uber headphone setup and the dynamics suffered and music sounded slow and bloated but it was the smoothest, least fatiguing sound I ever heard, also the best treble my system ever produced.
im currently using a Sound Application TT7 with a dedicated 20amp line using 6awg wire and it is excellent. It’s a dynamics and speed king, but if the washer/dryer are running, I get fatigue immediately, same goes for blow dryer, blender, etc. I get fatigue also depending on the time day. Nights and Sunday's are the best, but that’s not always the time I get to listen. Sometimes I’ll be ready to sit down for a session but the system is too bright and so I can’t listen for more than a few minutes. When I had the S1000, that fatigue was never there. I could listen anytime no matter what and it always sounded the same. Mind you, I live in down town Chicago with several hundred neighbors all sharing the same power lines.
Trying to fix this would need an electrician to run a power study on the house and that alone would cost several thousand dollars, not including any fix. Wife is also taking about moving in a few years, so any electrical infrastructure improvements would all be wasted if I moved.
Long story short, I have a S5000 High Power arriving tomorrow straight from the D’agastino office. I will be testing the dynamics specifically against my Sound Application TT7 240 PGI (but I’m not running big hungry power amps, only an Extreme and Sennheiser HE-1) Will report back.