The Andalite Chronicles is the best chronicles book imo, but I think she had the most time to work on it, I mean Visser is really good and it's also really short.
Arbron was my favorite character because he had a sense or humor but he knew when to drop it and focus on his job, and I like that he didn't just give up on life as a Taxxon, though he flip flopped on the matter at first when we first learn he was trapped he was still focusing on the mission, he still helped Elfangor after becoming a Taxxon and he still fought the Yeerks for years with that hunger.
I loved the space adventure, not being confined to one little planet, I kind of feel like the whole series could have been more like TAC after 54 if only it'd continued or had an EU.