The biggest usability issue I have found is that there does not seem to be a way to snap panels and windows across to the other OS. For example, Kali can only reserve workspace for its own desktop; not the Win10 desktop. The opposite is also true.
This becomes a problem when you have a maximized window in one OS, and part of it that you need to interact with becomes hidden behind the system panel / toolbar in the other OS. You have to temporarily move or undock the panel to get what you need.
There are a couple other weird things, but for the most part It Just Works.™
Seriously impressive stuff.