I'll think you'll find they are all beta (or possibly RC (release candidate)) by definition. As I understand it QuarkLabs is a test bed and anything that gets through will then hit the main Quark site's Xtensions download area with, possibly, a price tag.
Basically all the Xtensions in the 'Lab are there for testing, comments, feedback, etc..
Greg
I think therefore I am, you're pink therefore you're spam