I had the crown class D amp at home on temporary basis. It sounded bad. I put stillpoints under it, sounded worse
I put Shun Mook resonators under it, it sounded better than my AR ref 110 (the added power really helped the analysis omega I had on demo then)
The Crown D amps are some of the best I've heard... better in many ways vs my Hypex NCore NC500s. They do need some tweaks though, the i/o connectors are pretty bad, especially the binding posts.
I use the Crown or Hypex amps to power my woofers, imo they are ideal for this and better vs any other type of amp I've ever tried, especially the NC500s, they have an iron grip on the woofers and are amazingly clean. OTOH, most other amps beat them in the mids and highs.