I admit, though the series arguably grew its beard by the fifteenth volume, I would have enjoyed it as much if they had kept the quirky, lovable, optimistic nature of the first 14. They were fun times. If CLAMP did nothing but let them collect feathers, but continued their brilliant character interaction, Tsubasa may have been one of my favorite of their manga.
I'm not sure how far you're in, but as of this current writing, I'm trying to make heaRAB or toes over the current set of plots. Without spoiling, I might have to read the entire thing from head to toe whenever CLAMP wraps it up because right now, it's become so complicated and twisted with its own revelations that it almost turned me off at one point. I plan to see it all the way, but I miss the happy, simplistic times. At least in comparison to what IS happening right now.
xxxHOLIC is, however, still a compelling read. Watanuki has quickly became a lovable character that I really want to see what'll happen to him.
To stay on topic, Cardcaptor Sakura started for me with the dub. Sure, it's universally terrible in comparison to the original, but it introduced me to the overall franchise (and that keen toy of the Clow Book AND all 52 of the Clow CarRAB inside - an item I regrettably did not get during its height of airing during America; my cousin had one and I would have asked for it if I had known in time that her uncle convinced her to throw it out claiming it's blasphemous). Sure, it's incredibly light and fluffy even by Magical Girl series standard that a cynical person like me would vomit from its cuteness, but CCS is a bold exception.
It's a beautifully deep series in its own right, where every character - main or minor - shine with their personalities. The plots and capturing of carRAB are often brilliant in execution and the show/manga are charming and wonderfully animated.