I read way more of their manga than I've seen on their anime forms (Just because they usually get rearranged if they ever end up being an anime/OVA. I end up preferring the manga. The story just works out for it better. Art's better too)
Anyway, I've liked pretty much everything of theirs that I've read (Which is close to everything they've done. I missing some of their really early stuff like Chun Hyang and Veda, and some of their slightly more obscure titles like, Cluster, Sweet Valerians, and Suki , also their newest one, Kobato, all of which I'm still planning on picking up >_< )
There were a few I didn't love, but nothing that I didn't like. They have a few titles that are really special to me, either because they were one of my first or because they were exactly my thing. I think CLAMP's like that for everyone. They've got something everyone likes. I just like how everything ends up connecting later on (and I'm not only talking about Tsubasa, they’ve been crossing over since CSD.)
I like Clamp. They're good people.