I've occasionally experimented with Cliptoolz V2 out of interest, but found the formats I wanted to convert exhibited large changes to the final colours in the files, so weren't usable.
These are the only three formats I'd tried before and recently tried again, playing with a clip uploaded by @jensfieldler in another thread.
ProRes HD (All options) changes the palette significantly - See attached images and flip between them to see the image change, as well as the histogram.
ProRes 4K gets it 98% correct, with very small changes (sometimes up, sometimes down on different frames) to all the values displayed in the Histogram and the image looks fine.
DNxHD HD gets the values mostly correct, although there are some gaps in the Histogram, which looks like the range was compressed from 0-255 to 16-235, then stretched back to 0-255 again. Image looks fine, although it's not the best choice to see if banding or any other artifacts are visible.
Also: I do miss the ability to drag'n'drop files into it that V2 allows, that's been removed from V3 for some reason.