I got a used Devialet 220 Expert Pro for under 5,000 $.
This is an amazing amp . Fed with an Aurender and USB and using the SAM feature to extend low frequency response, it makes my Raidho X3 speakers sound so clean that you forget about them.
I can only respond to what I know personally. I haven't heard other Class D Integrated Amps, but I own a Rogue Audio Pharaoh II. I've owned the Sphinx V1 and V2 and then moved up to the Cronus Magnum. Two months ago, I traded up to the Pharaoh II and can't say enough how good this amp is. Powerful, quick, completely black background, great soundstage with clean, strong highs, midrange and bass. I cannot be happier with the purchase, and you're well below your dollar threshold. You should at least demo this amp for yourself.
Guys, why is everyone ignoring an obvious star in the line-up PEACHTREE Nova-300 or the new GAN. I have had mine for two year and am still blown away by the performance-to-price ratio and I'm not alone.