I have used many different components over the years. My company recently charged me with developing a Community Based consumer site and backend for our existing Gift and Loyalty card product. Short of writing my own extension from scratch - I tried out Chronoforms. This, is without a doubt the most flexible extension available for forms and database manipulation. There are 2 things that make this a home run.
1. It is relatively easy for a beginner to use and get an immediate result.
2. The support is SUPERIOR!!!! The forum is active and responsive and the moderators answer ALL questions.
Way to go ChronoForms!