I created a WordPress account just to agree with this. I have never seen such good support at this price point. Within a day they had me able to do a custom solution that wasn’t even originally supported (NOTE: I needed to know PHP, don’t expect them to write custom code free for you, I don’t want my good review to just cause them headaches of ridiculous expectations).
That says something about both the support, and the quality of the software that is flexible and designed well enough meet your needs. If you want a super duper amazing simple form, you would be fine with this or the other solutions. But if you want a form that can also feed data back out to your site in incredibly flexible ways so that you can actually, you know, use the data that the form just captured, then this is it. I have already saved $499, not because I was being cheap, but because I was able to write my own functionality quicker than I could learn how to use an off the shelf solution to a couple of projects.
Some might consider it an insult, but to me Formidable is like Visual Basic for WordPress (OK, maybe Delphi).