I use Breezingforms for over 40 forms on my company's site. From simple contact forms to a very extensive employment application. It's also great for conditional fields and complex calculations. It's easy to get the hang of, but, the support is so amazing that they actually do a lot of that for you if you ask.
Recently, I had a complex form that calculated a cell phone plan and I couldn't figure it out. Sent an e-mail and Stefan built the script for me - you don't see support like this that often.
I love Breezingforms and my job depends on it.