I'm done with Tsukihime and Kagetsu Tohya now. I really liked Tsukihime for the most part, but it got pretty repetitive at times. You know about the backstory, relationships and true nature of certain characters after playing through one route, but then you have to wait around for it to be revealed in every other route as well just because Shiki hasn't learned about it yet in them. I would have preferred if they had put all that stuff in a shared common route instead, since it's boring being fed information you already know over and over again. It's also pretty stupid how some major elements of the story randomly changes depending on which route you go down, although the prerequisites are the same.
Another annoyance was when the game decided to go crazy with random nonsense just to seem deep/disturbing/whatever. It just looks stupid to me. One example:
As for Kagetsu Tohya, it sucked. The story was utterly uninteresting, and not even the comedy stuff, that the VN relies quite heavily on, was very entertaining. I might reread Tsukihime someday (especially if the remake is ever released), but Kagetsu Tohya won't be a part of that deal.