Look what’s featured in Apress’s weekend sale! Ebook only, I believe. The code is W3BD3V, good through Sunday.
I’m guessing that what you’ll get is the Alpha edition — a PDF of the in-progress chapters, with the EPUB and Mobi editions appearing in your account in two weeks or so when the final book is published.
The last few chapters are being copyedited now (fixing typos and code line-wrapping issues, mostly). I’m keeping an eye on the last-minute changes to the post formats feature, but otherwise the content is locked down, so what you see now is more or less what you’ll get in the finished book.
I just saw the final cover (front and back) on Wednesday. As with almost everything about this edition, I like it a lot better than the first.