The music is gorgeous, so props to whoever composed it - however, I do have a small complaint. It doesn't fit the theme. It's what I'd classify as "trance" or "chill" and it's very slow, cosmic, and somber.
The basis for these skins is anime magical girls, and if you've ever seen shows with this theme, you'll know that slow, somber, trance music is about the furthest thing from this genre of bubbly J-pop, energetic electronic music, and powerful love ballads. So while the piece that on the PBE is beautiful, it doesn't fit the thematic whatsoever. I would recommend sidelining it for use on a later champion or skin and making a piece of music that fits the Star Guardian thematic more.
As compared to: