Although one should always be skeptical of audio reviews due to quid pro quo, this statement is quite the endorsement. I know that NuPrime has specifically tried to mimic the sound of linear amps (if you read their marketing copy) so their engineers may be doing something right.
I’ve heard many class D amps, but have liked very few. While bass control and neutrality are often a piece of cake for these amps, they are usually let down by thinness, harmonic deficiences and an unnatural timbre. The NuPrime ST-10 is the first class D design that sounds timbrally wholly convincing to me. Piano really sounds like piano, not like synthesizer and vocals are just as direct-coupled as they are in real life. Add in bass heft and thundering dynamics like I have not yet heard from other class D designs. Only the Mola-Mola Kalugas ultimately provide more refinement and transparency but these are placed at the complete opposite price spectrum.