I have used Fabrik on several websites, and I am seriously happy with it. I created games where gamers answer questions per mobile phone, including an entire backend system for game-editors, but I also used it as job vacancy system for a multi lingual IT company. Guess what, i know aboslutely nothing about sql and still managed to get this all working.
The support is good, issues get solved (I became a 'bronze supporter' to get them solved within a timeframe of 24 hours)
It takes a while to get the hang of things in the beginning, but it is well worth your while to dive into this. It made my joomla websites truly interactive!