Pluses are: rich functionality, many questions types, media content, feedbacks, categories, shuffling and possibility to miss questions.
Its admin area is quite intuitive and it's easy to install on standard Joomla!
There was a case when support team helped me with custom version. After they added new questions types I started like this extension even more.
Waiting really for Joomla! 3.0 compatibility.
Extension is integrated with the JS and CB that is very useful in case you need an integration.
In the beginning I had some minor issues (my fault) but the support team was very efficient and fast to solve every issue and now the component works very well.
I highly recommend this extension if you have a community site as the testimonials are shown with the user avatar and appear very realistic!