I saw a basic list of features, but nothing that explains what they are or how they work.

well I know that the current documentation on the zend framework web site is for version 1.5

Even though it's only in release candidate phase? I thought they would wait to update it until it was official. Also I thought I read that things could still change with it and that this release was locked yet.

My understanding was that it had gone past that phase and they are encouraging ppl to use it so it has been widely used before they slap the 'official release' seal upon it.

I upgraded my library last week and I had NO problems upgrading at all. One shouldn't have any problems unless they have been doing strange modifications to it. v1.5 has some great additions like Zend_Form, Zend_Layout, and additional View Helpers. try it out!