Well, here it is, a run I've wanted for quite some time now.
Utsuho is by far the most atmospheric final boss to ever grace this series. Everything about the battle fits really well together: the music, the annoyingly bright radioactive bullets, the gigantic sun bullet danmaku, and the... whatever that is in the background, the nuclear symbol with the cat on it. To put it simply, it's intense.
The stage portion is pretty straight forward (in this run, things got a little too close for comfort against those crows that crap all the large white bullets), and the same goes for the midboss encounter with Orin.
In my opinion, most of Utsuho's difficulty comes early on (actually, I don't think anyone would disagree with this). Her first card is tough, but I've noticed that when I play more defensively on it (as in, not try to capture it ASAP), I tend to fair far better against it. Her second noncard always seems to backstab me when I least expect it, but small movements and a little luck with good openings--as this run demonstrates--allows ReimuA to take it out within 1 iteration. Her second spell card is random and annoying, so I honestly don't know what to say about it :P
Aside from that, the rest of the run came down to nerves and whether or not the last spell would shit in my face. Luckily, everything went according to plan. Funny thing is, the last few runs immediately before this one had me failing the last spell left and right; I'm not talking about dying once or twice, I mean dying all the time without me understanding why.