One issue that I have with the user blog, is the Consistency of it's appearance. When you go to create a blog or leave a comment, you get the forum layout instead of the blog layout that can kind of be disorienting.
It include a few minor changes and minor bug fixes.
The biggest change is the new function that is included for the plugin system. The new function makes it easier to develop and use plugins which use their own templates. It also prevents errors occurring when using alternate blog styles which do not have the template required for that plugin and uses the prosilver template for it instead (all blog styles should be designed to accept prosilver template sections for the left menu so they may use the default).
Also I have just released a new plugin for Blog Tags. This plugin only works on RC2 and newer.