Dark view is not that great, and most of my apps are not adjusted for it [yet]. The Mac App Store is HIDEOUS! See my forum post... In general, I think it might be best to wait out a few releases before jumping from HS. I normally do that, but figured given Apple's attention to under the hood stability fixes things would be OK.
Don't get me wrong, I haven't experienced any show stoppers.
However, I haven't delved any deeper than a few apps. And given the Mac App Store abortion, I suspect there may be a few other things waiting to be found.