Most of CLAMP is rather good, but Chobits is--well, I'll be charitable and say that its garbage. I say that in regards to the anime, if you must have a look then follow the advice of others and look at the manga. I don't know how much of an improvement it really is, but then again I'd like to think that you can't really do worse than that Godawful show in the first place.
Tsubasa the manga is great. The TV show is...uneven. The score is amazing and the show can be entertaining but it can also really drag sometimes. It certainly did at the start after the first episode, streaching out the first arc for much longer than it needed to be. Then again we've also have situations where an entire visit only takes one episode. My full opinion on it is incomplete, but I will agree with what others have said and say that if you read the manga you can't go wrong.
I would suggest that it's not the medium, but the quality of perception and expression, that determines the significance of art. But what would a cartoonist know? -Bill Watterson