Here's a very unofficial response to that question.

I did an install from the CVS code a few weeks ago and here are some of the highlights as far as I can tell:

1. A built in file manager. This looks pretty slick. You can upload and manage files.

2. Multiple blogs across separate subdomains and domains. One install of b2evolution can run blogs on several domains.

3. Reworked stats and antispam. I'm hoping this will turn the tide in the battle against blog spam.

4. More plugin hooks. Right now you can only do so much in the way of writing plugins. The new version should be much more extensible.

I'm sure a dev or at least someone who knows much more than me will come along and correct or extend this list, but those are the things that I noticed.

There's always this file you can snoop into:

http://cvs.sourceforge.net/viewcvs.py/evocms/b2evolution/doc/changes.html?rev=1.103&view=auto

Thanks, guys. That's good info.