The main emphasis is on improving support for braille users, but there are also changes for browsing, Microsoft Word and Open Book, among others. Lots of bugs are squashed, too.
As someone interested in eBook reading, I'm glad to see that in the latest Adobe Digital Editions 1.8 Preview, the Say All function now automatically turns pages and so will read until the end of a book, unless you stop it first.
Reference is made in the release notes to Windows 8, so they're obviously working hard on that in time for its release.
It's too early to say more until I've used it for a while, but I'm looking forward to installing it and starting to play!
By the way, if you like the idea of NVDA, please consider donating when you download the software. Although the people behind NVDA get occasional support from large organisations, they aren't salaried and depend on donations to continue their work.