Had a few issues with the extension but contacted support and it was fixed there and then.
I would rate 5 stars but unfortunately adding questions is overly complicated and the backend admin is done alot better in the free extensions.
But the look and feel of doing the quiz for your visitors is fantastic.
Next release id like to see:
-Ability to restrict users to 1 attempt
-Better results & filter
-Bulk question and answer load, or improved system (ie answers in with the questions like jquarks)
But all in all a good app with excellent support. Pricey at $40 but support worth it.