In my opinion the best one is Queen's Shadow: not only did I like the plot itself, but I also enjoyed the way it depicts Padme and her transition from Queen to Senator. It has been interesting seeing how she built her public persona with her handamaidens' help, adjusting the figure of Amidala to her new role. Besides, the book also added some depth to Padme's character as well, not to say the whole environment surrounding her. The Senate is of course a different place from the court of Naboo, and getting to see how it more or less works has been good, considering that we didn't get many politcs focused scenes in the movies, and some of them even got cut in the end. Padme is an idealist: it was cool seeing her adapt to the senatorial ambience, which is totally different from the environment she had been living in until then.

Queen's Peril is good as well, and it is indeed my second favorite book in the list: as Queen's Shadow it gives a glimpse on a period of Padme's life, in particular the one in which she became Queen of Naboo. Again, I liked the description of the "making" of Amidala, and the choice of the handmaidens, because it basically tied the book to TPM, and it enriched its story. I pretty much liked the movie already, but now that I've read the book I appreciate it a lot more.

I can't say that I liked Queen's Hope as well though, and it is truly a shame for me. It is not bad at all, but in some points the narration feels quite static and the plot doesn't seem to go anywhere, as if it wasn't progressing at all. In some parts it felt like the forced conclusion of this trilogy. I had high hopes for this book, as I had thought it would cover a different time period of Padme's life, answering to some questions and dilemmas that are still unaswered. Instead it is much closer in time to Queen's Shadow than I had expected. Which isn't necessarily a bad thing, but I suppose that the period that goes from Anakin and Padme's marriage to the end of ROTS is much more interesting to analyze for various reasons, in particular showing the relationship between those two characters. We already know them as "public people", but it would have been better, at least to me, if we saw more of their personal life. We got more of that with TCW, but I think that some things could be explored further: the secrecy of Anakin and Padme's relationship, the way they actually managed to keep it more or less that way, the tension building up until the events of ROTS. There were a few brilliant and entertaining moments, some even touching, considering it is the end of a trilogy, but nothing more than that. Overall I enjoyed the book and I'd recommend people to read it, but honestly, I was expecting a little bit more from it.

Haven't read them yet but the first one is being shipped to me as we speak.