Ooh, I read them! I got up to 64 or 72 before I stopped. I was also older than the target audience, but I really enjoyed them. I'm not sure who I could pick as my favorite, since each girl had something I could identify with. I think my favorite book is the super story where they went to Disney World.
I think I finally gave them all away to my cousin when I was 18, which was about a year after I stopped reading them.