I can see what you mean about the music if you're listening at a normal volume. For some reason it works better if you turn up the volume by a couple steps and you can feel the bass in your throat, but that may also just be my taste.
Not sure what other music genre you could use for a magitech Utsuho fight. Maybe trance, like the intro.
It's really hard to beat the music selection of Reimu vs Yuyuko though, that was masterful.
Reading this, I could agree about the music, but again, compared to the previous works, they have a good feel along with the animation.
Let me discuss the other works
Reimu vs Remilia has a good track, not perfect, but is a good scenic track already so that's why I liked it.
Marisa vs Flandre got a good sequence of music, especially for the last track for an epic finale, like it was some not-so-serious fight, but instead enjoying the fight with display of power.
Reimu vs Yuyuko has an inarguably good track coming from the start, until the end. The chaotic yet calm feeling from the stage was expressed by it. During Yuyuko's fight, it fitted perfectly by showing how beautiful Yuyuko's danmaku was. And of course that resurrection track was grand, especially that part where Yuyuko really "blasted for real" lol.
Seeing Humans vs Yukari, the first one is, hmm okay. But when it came to the part where Sakuya comes in, everything fell into place. Not only that, the xi-on remix had an awesome feel through the fight until the very end.
And now, about the present one, Subterranean Stars. It's really good, but it bothers me on some points.
Seconding this. The remix by Kanpyo's MIDI just rubbed me the wrong way. I mean, it's awesome but definitely not quite fitting in this case, even though minusT synced video to music as best as possible. Other themes fit greatly, though.
Surely, some other tracks would have been capable. But what else can I say, thank God minusT made it possible to display that fight.
And pardon for the criticism I've shown.