i have not compared, but i have the 600 and it has as much power as one would need ... my speakers have harbeth mon 40’s, super 5’s, and large spendors, as well as magnepans
it is a lovely amp with a silky smooth yet sufficiently impactful and transparent presentation, it just takes a little of the edge off of poor recordings that need it -- plenty of control and slam down below, as per top flight solid state amps... no softening at the bottom
the nuvista amps and dacs have always been musical fidelity’s finest work