I've heard tons of rave reviews about this manga, but to be completely honest, I've never been able to finish it. Even my guy friends tell me how good it is, and I just don't get it. So I finally sat down and said "Alright! I will get through it this time!" and finally did.
There are lots of good things about this manga. The characters grow, change, figure out their flaws, try to fix them, and are generally likeable. The plot is more or less interesting and the interaction is great. The romance is also there (in great heaping dollops.)
What bothered me to no end, though, were a lot of really basic things that I can't help but feel should have been gotten right somehow.
A) The dialogue is horribly disjointed. I don't know if this is a scanlation thing or a style thing, but it's all over the place. Towards the end, I could barely tell who was saying what, and the mangaka's love of word bubbles with stuff like "this--" "happiness--" "and my--" "feelings--" "toward--" "that person's--" "anger at them--" is really hard to make any sense out of (especially because she usually doesn't indicate who's saying it, which makes it even worse.) That really took away from my enjoyment of the story.
B) It gets really hard to tell the characters apart. Fruits Basket has a horde of characters and a terrible case of Only Six Faces. To make things worse, several of them have similar hairstyles, or they cut/change their hair and clothing halfway through the manga, which really throws you off. There's "growing up", and then there's "becoming unrecognizable", and it mostly does the latter. (Kagura, for instance, starts out as a frilly, toy-carrying whirlwind, and toward the end chapters she shows up in a shirt and pants with her hair tied back. Gyah!)
C) Holy moly the angst. It's everywhere. The angst is everywhere. The whole Sohma family is comprised of people with angst. Combine that with disjointed dialogue, and I'm surprised it turned out as gripping as it did. This mangaka sure knows how to tug at heartstrings.
(Also, speaking of the whole Sohma family, all the intra-Sohma romances did end up feeling slightly incestual. But I guess when your family is the size of a small village, that sort of thing can't be helped.)
Overall, it's a good manga. It takes a bit to plough through the middle part (there were 50 chapters or so that just dragged), but it starts well and does get good, so if you're into enormous love stories where everyone lives happily ever after you might want to give this a shot. At it's core, though, surprisingly, Fruits Basket is neither about zodiac animals, romance, or hot men living in a house. It's about parenthood, more or less. It's all about parenthood.