I'll add my +1 to that one. Fusion stand-alone has an immensely flexible UI, with the ability to split panes, tear them off into free-floating windows, put any view into any panel, and save those layouts for later use.
If you're an enterprising sort, you can even get in and reskin Fusion—its appearance is controlled by a stylesheet wrapped in a disguised zip archive.
Quick example: When using some tools, it's useful to be able to stretch out the Tools panel (Inspector in Resolve parlance). Resolve's Inspector has a fixed width and in some cases
way too much whitespace. Here's a screenshot comparing the ColorCurves tool in both:

- Untitled.png (51.06 KiB) Viewed 1316 times
In Fusion, I can make it much wider, giving me more precision when setting points (yes, I know I can get an even bigger graph in the Spline View—that's not the point). Resolve, on the other hand, has a teeny tiny little graph, yet fully 20% of the panel is empty.