I don't like the original story (Alice in Wonderland) because I think the characters are mostly insipid, and all fairly one dimensional. However, I love this series where the characters are more real to me. The good guys have their flaws, the bad guys are pretty much nothing but pure evil, and the fantasy element of it all is fantastic.
Seeing Redd does fall prey to the most commong of complaints when the second of a trilogy. There's no origin story to make you embrace the characters, the action can't be wrapped up because there's one more book to go, and the reader is left wanting something more. When I read this the first time I was mostly frustrated because it had been out for about five hours when I finished reading and I knew it would be awhile before I could finish the series. The second time through, I liked the story better knowing I had Archenemy in my hands and could start that as soon as I closed Seeing Redd.
Redd is such as villianess like villian. She can be a little cliche, but I think that's because she is SO evil that all other evil is really just an imitation of her. She's the origin, all other evil is the cliche.
Wonderland politics also play a larger role in Seeing Redd than they did in The Looking Glass Wars and that was interesting. The struggle between the Wonderland Queendom and the Borderland Kingdom (complete with a chauvanistic king) was fascinating.