Yeah, it’s stable, but there are a lot of UI glitches. Stuff like the divider between the main view and the inspector disappearing every time you resize the window in any app using a standard inspector (such as Preview or Xcode); glass buttons not always adapting correctly to the background colour; new UI elements introduced for developers to use with glass (like new header and footer bars) not yet being usable at all; developer tools for setting the toolbar divider style being broken; toolbar subtitles barely being visible above background content behind the glass; the standard PDF view’s navigation features not accounting for the glass nav bar; on iOS, keyboard avoidance code being completely broken - and many more minor visual issues.
I actually like the Liquid Glass appearance, but I seem to have spent more time over the past three months reporting bugs to Apple than anything else. (Apple won’t look at a bug unless you provide a sample project demonstrating the issue, so writing a bug report and putting together a sample project for them frequently takes an hour at a time.) It’s frustrating to then see the OS released with only one or two of my sixty bug reports receiving an answer, and to have to spend so much time trying to find workarounds.
Anyway, moan over. 
I expect these issues are worse for developers than users, and even then it’s always more complex UIs such as Scrivener’s that tend to expose edge cases that Apple hasn’t accounted for.