Style Radio doesn’t work well with my music collection, but I figured out how to enable Genre Radio. I’ve been searching the forums and this helped: Plexamp - Expose Style Radio when library Genres set to 'None' - #2 by elan. I needed to set Genre to None (until this is fixed and then it should be Embedded Tags I think???) for my music library and then Genre Radio replaced Style Radio. I’m happy. Thanks for supporting Genre Radio. Essential feature for me - call me crazy with my carefully managed ID3 tags. 
