The real issue with the Class D amps is they lack the headroom to really be loud enough. IMO/IME with the EHX .22 Caliber and others in the same power range, the lack of headroom doesn't make them great for a stand-alone amp unless you plan on setting it to the side and mic'ing it up through the PA so you can really hear it. These things need to be "clean" since they are supplying the power amplification. And Class D amplification clipping by itself is not a pleasant sound. That's my 2 cents.
Now, I have not tried the Quilter so it's totally possible that Pat has changed the game, yet again. He makes great stuff.