Nice extension to allow guest and users put some reviews of your website.
But it is very interesting because you can think of it as a lite and straight question and answers component, as i did for a client website. And this is great, because most of Q&A components out there are commercial and full of features that are not very useful if you are going to have non-geek users for your website.
Put message -> answer messages (with ACL support). Yeah! Keep it simple, great work. Promisiong extension indeed.
CONS: it is still a little buggy, specially in IE 7-8. But support is fast and they are updating very frequently the extension.