PHPLIB

I'm starting to use phplib. Any opinions on it's uses. I know zend uses it. I intend to use the template feature and database abstraction. I would also like to set up a simple cart using phplib. Any thoughts? Any experience from those using it would be greatly appreciated. While I'm at it, any opinions on what the best gpl forum software is? Which forum code does phpbuilder use? Did they write it, or was it obtained as open source code? And how about knowledge base stuff? I'd like to set that up too. Many thanks. The php community rocks! matt.