I tried Flexi Contact and had it installed, configured, tested and running perfectly within about 10 minutes! VERY easy to configure and so far seems to work exactly like it's supposed to!
Also, it was VERY easy to customize with plain ol' CSS in my template :)
I wanted to change the look (color scheme) and the developer was VERY helpful, very quick to respond, and very kind in answering all my questions to point me in the right direction. He really went "above and beyond"!!
It was not hard at all to change the whole look to suit my own template, and I am beyond thrilled with this extension!!
I'd recommend this FAQ Book extension for anyone interested in putting together a very nice, but "clean" FAQ that also allows "thumbs up" (or down) for each question, as well as allows users to add a new question that you then are able to answer and approve if you so choose. :)