This amp originally retailed for $2495, and based on other older Class D amps, the used price is about right. That being said, here's a review:
This is one of the First Generation Class D amps. Back then, there was ICEpower and Hypex class d technologies. Both had problems and the frequency response had a tendency to be driven by the speaker's impedance curve. This could result in weak bass, uneven frequency response, rolled off highs. I owned a set of Channel Island amps, which were of the Hypex module. They were very nice, but they did not react the same with each speaker. In the end, I sold them because a high current Class AB amp just sounded better. Hopefully, the following links come across:
The new ncore Class D solves a lot of problems with speaker impedance. However, I have found I just do not like the Class D sound. I have heard a few newer Class D and they are extremely clean amps. The problem is they are so clean that it is almost too clean. They did not have that "organic" feel and did not reach out and grab me. Not emotionally engaging. The one ncore option that I would consider (of I was looking at all) is the Nord "One Up" model, which uses a Class A input buffer to help shape the sound. The Nord "One Up" stereo version is going to be about $2,000 US shipped. Please be aware that the Nord multi-channel amps do not have this Class A input stage.
These are my own opinions that I have formed. There are many others that love the Class D amps.