My favorite characters were always Kristy and Claudia. My friend who watched the show with me (but never read the books) said that he couldn't stand Kristy. I think that the show didn't do the best job of making Kristy look sympathetic. I remember that Watson's house was described as being "on the other side of town", not at all walking or even really biking distance. The club had to pay Charlie to drive Kristy to and from meetings. This wasn't the case on the show, as we saw Kristy casually walk to Watson's from her house while Mary Anne was babysitting for Karen and Andrew. I feel like pointing out that Kristy was losing proximity to her friends at an age when not being able to be near them all the time like she was used to would have made her much more sympathetic. Sure, they talked about how she and Mary Anne wouldn't be able to use the flashlights anymore, but they brushed it off with, "Oh well, we have cellphones." The way the situation was portrayed in the show, my friend just said, "Oh well, at least she's rich now and has a bigger room. What's the big deal?"
Kristy was the shortest club member by far in the books, and Claudia was described as looking more mature. I feel like they swapped in the show, aside from their fashion choices.