If it has worked, it would have been great that you can process credit cards right there in the form. It's also nice how you can save form sections, and there are many options for question/answer templates.
As soon as I started using Formstack, there was an issue with the payment processor integration where credit card transactions would not go through. I started out using Stripe, and when it didn't work, I contacted support, but none of their solutions fixed it, so I switched to Paypal. I then had the same issues with Paypal. I emailed back and forth with Support for a long time. They offered me the same 4 solutions repeatedly, all of which I tried. I explained to Support that these things weren't helping but it was as if they had amnesia and didn't remember they had already suggested the same things, which didn't work.
I sent a message to the Sales team instead to see if they could get me in touch with a different Support professional who knew how to fix this problem (no phone #s on website). Sales said they would escalate the issue. When I didn't hear back for a week, I emailed again asking to cancel my account, and the Sales person said they had emailed support and that "the issue is with your payment processor," which of course I already knew and was the reason for my message in the first place. They continued to insist that the issue was with Paypal. I talked to Paypal support and the problem was not on their end.
Many annoying issues with the form creation interface too- like to move questions you have to drag and drop by scrolling through the entire form. And the item/event purchase requires you to give the option of ordering more than one of each item.
Response from Formstack
We feel just awful that you had this experience. I sent your review over to our Director of Customer Care. She had a meeting with all of the support team leads to go over your experience. She said she would really like to chat with you, on a call, and give you two months for free if you'd be at all interested, just to ensure you can get up and running again. Her email is Jessica.Haas@formstack.com. While we have won awards for our excellent customer support, your experience has pointed out some glaring issues we're taking care of immediately. We'd still love the chance to make this right for you, but understand if you're not interested. Either way, thank you for the review and helping us improve our customer support team!