I'm not giving you a single spoiler because that would, well, spoil it. Get it now and enjoy Jo's writing. I always do.
As an additional incentive she's giving away some gifts. But rather than do it very badly myself here's a link to her own blog which as always look gorgeous.
I don't read nearly as much as I should but I have all of the Amaranthine series so zip on over there and have a look.