I just finished watching season 1 + OVAs of Starmyu. I'm writing my review now because season 3 recently started airing and I expect the series to remain consistent across seasons.
Alright, so this literally feels like a musical. For me this was great. There are plenty (at least once/episode) of dance/song sequences, which I found really enjoyable. One of my favourite aspects of the series. I'm a huge sucker for that sort of thing. On that note though I'll mention that the character designs are kind of bland, however I can't really fault the staff for this because of how much movement (dancing) needed to be animated. I didn't observe any CG being used. There are a variety of cute dance outfits!
The characters themselves were cute but in some cases were poorly/under developed. I suspect this will be somewhat remedied in later seasons. The cast is relatively large and the first season is only 12 episodes +2 OVAs.
The OST is decent. There are some good songs like character songs and such. I liked the ending sequence. https://youtube.com/watch?v=2kLyUptu2Bg
Unfortunately, music for this franchise has been difficult to find so I'm hoping that the airing of season 3 will trigger greater availability of audio content. Otherwise I may have to suffer the indignity of ripping from YouTube or something.
In terms of writing, there is some 'forced drama'. I loathe the term but I think it's accurate here. There's also plenty of ships to set sail.
Overall the series is decent and it basically 'does what it says on the tin'. I'd rate it 7/10. If you like musical anime and/or boy idols then you'd probably think it's decent. Appeal to a broader audience than that is limited I think.
Tengenji is so hot
Finally you should know that I may be biased because many years ago I used to program/build theater lighting systems (I'm severely autistic), so I've worked on a few musical theater productions. I have a soft spot for theater in general.