The storyline is wonderful, the sound track is amazing and the characters all give an extra plot twist to the real storyline. Sadly, the anime doesn't really reach a point that it actually gets to the main storyline.
Tsubasa Chronicle is a good show if you're a shoujo addicted fangirl, looking for some new anime. But it's certainly nothing good for the die hard CLAMP and TRC-manga fans. If you have no problems with reading the manga instead of watching the anime, I'm telling you, go read the manga.
Animation is a disappointment. Art is also pretty screwed up. Even I, someone without eye for animation quality could see it.
This anime = A no no.
The OVA = BIg yes.
The manga = to die for.