The upgrade was pretty smooth for me overall. I updated a total of 43 switches for this site, models include MS425, MS355, MS120, MS220. Everything worked great (including one MS120) except for three MS220s I have, which basically all needed a factory reset and two of those needed to be goosed by support. I'm not sure the overall fix I was looking for is there, but I'll have to do some internal testing to verify.
I did not have the PoE issues others were wanting to address, so I can't speak to those. It's pretty stable, so I'll roll it to other sites soon.