It was striking to me that she said that her favorite voices of the cast are those of actors who were untrained as singers when they were cast, though I make a distinction between untrained and self-taught. Glorfindel is a vocal coach, and has made observations about the improvements vocal training has given to the performers who weren't trained singers to start with. But see the second half of the Finn review where she gives her personal opinion. It seems like she can totally separate out what she'd critique as a vocal coach and what she enjoys as a fan of the actor.
I'm more critical of Finn as a character now that I've seen lots of meta about him, but I enjoy his singing. I like rock and roll, and a lot of Finn's songs are rock songs.
As for my tastes in music, in addition to rock, I like Industrial and heavy metal, and some pop. My tastes are varied. I'm not a fan of rap or country music. I'm not especially a fan of oldies, and I'm not a fan of show tunes in general, though there are some Kurt show tune songs I like. So I mostly judge by what genre I like.
It's interesting to me to get the perspectives of people who are skilled in judging acting, singing, dancing and costumes. I would say that I especially appreciate the singing critiques. Glorfindel teaches as she goes through songs.