Overall, Ten Desires is a good Touhou game. Not my favorite, but definitely not my least favorite. I feel that the difficulty is less than SA and UFO, I find it somewhere around just below IN when it comes to normal mode. I got a normal 1cc on my first try, and I didn't even run around bosses to get spirits until Stage 6. Hard mode took me about as many tries as SA hard did, which was around 5. I tried this game on lunatic solely for unlocking spells in spell practice and I failed horribly. I've 1cced PCB and IN lunatic, and got to lunatic Remilia once, so I'm by no means bad at Touhou, just nowhere near the best.
The stages are kind of boring, the music is kind of meh (extra stage has the best over music of all of them, Futatsuiwa from Sado is my second favorite extra boss theme), characters seem interesting from the dialogue I read online, Youmu's back and also rather OP if you can time the slashes and move unfocused well, Trance can be used but not really abused if you're playing for survival, the extra stage is one of the more brutal (beaten only by GFW's I think), the boss fights are fun though, if not easy.
The stage 1 midboss...easy, obviously. It should be, but farming spirits on it can have a wisp spawn on top of you. Yuyuko has 3 or 4 spells, more than any other Stage 1 boss, and only the last one has any chance of killing me if I'm not paying attention. Kyouko has cool patterns, not hard to avoid, but still cool and I like the bouncing bullets gimmick. Kogasa's attacks are basically the same, and not that hard (except her spell on lunatic), and Yoshika's healing is cool but annoying. also CURVY LASERS, part 2, act 1 on her last spell on hard/lunatic. Said spell took me 65 or so tries to capture. Seiga's midboss encounter, if you trance the fairies before her the nonspell is skipped, her spell is really fun and seems like timing it out would get hectic. Seiga as a boss, I like the gimmick of Yoshika coming back, but CURVY LASERS, part 2, act 2 is kind of annoying. The Stage 5 midboss who's name I forget, the spell is confusing at first but once you get it, it's an easy capture on all difficulties. Even Overdrive. Futo has a boat. Not as nice as Komachi's, but still a nice boat as it makes her a bigger target on 2 spells. Overall a fun fight. The stage portion of Stage 6 gets a special mention here for being the most fun stage portion of a Stage 6 in Touhou, despite having lasers. Miko...her nonspells are honestly harder than her spells. However, some of her spells (namely the 2nd and 5th) look visually stunning, and the music that goes along with the fight is awesome.
The spells as a whole are very easy, almost all of them took < 25 tries to capture, while Imperishable Night had easily 50 spells with 50+ attempt counts. Seiga's overdrive, also known as CURVY LASERS part 2, act 3, revenge of the curvy lasers, took 321 tries to capture. The most for any IN spell was 281 for Fantasy Heaven. The overdrives were fun, aside from Seiga's, and all aside from Mamizou's and Seisa's took < 10 tries. The last spell in the game is underwhelmingly easy, taking 5/3/3 tries to capture on normal/hard/lunatic.
The extra stage, the stage has the most rigid path of all of them, aside from maybe UFO, Nue is one of the easier extra stage midbosses (her last spell is so fun though), despite her first one being unpredictable. Mamizou's animal danmaku gave me a "what is this I don't even" at first, and her spell are some of the more fun/easily trivializable. Her nonspells are my favorite of any extra stage boss. Her survival card is the most annoying of the other extra boss survival cards.
Challenge runs on the main game are either very annoying or impossible; no focus being the lone exception. When I did that I found it far too easy, having 5 lives (out of 6) going into the final stage. No vertical is impossible, or very close to it, due to Futo's final card and Miko's final card. No bombs is very unforgiving, and no deaths is always annoying.
Compared to every other game I've played, this is one of the better ones. Compared to other Touhou games, it isn't. However, I still enjoy playing it.
Also, YAY, YOUMU'S BACK!
tl;dr, I like Ten Desires, and it gets a 7.5/10.