Which owners? I am an owner and I would never say that. The Evo One is very balanced and musical.
I would say the evo is transparent and will pick apart poor sources or equipment, but if your system is put together well it will reward you.
To me the only weakness of the evo is the amount of power it has. When I read review saying things like "endless power" or "handles difficult speakers to drive with ease" I pretty much dismiss the review.
When I tried smaller speakers this wasn't a issue as my subwoofer's "had" to carry the load. But when I pushed some kef r900's, focal 1038's or b&w 803's..... well the evo amps simply could not push these speakers to what I know they are capable of, and again the subwoofers have to be introduced.
Now don't take that last statement as a rip on the evolutions as the other amps I heard were considerably more powerful, a pair of Brytson 4b3's, simaudio 400m's
And when I talk about power its not about shear db, its about making drums, bass guitars, grand pianos or even cellos grab your attention and make it feel like its right in front of you. I also prefer to listen to music a bit hot on the bottom end too

So nuprime needs to make a amp with the precision of the evo and the power of a bridged bryston 4b3