Bramblejam is a user of Jotform and the interface, service and technical support are great.
The Interface is simple and and straightforward: you drag your elements from the element section to your form area. When you finish, you view your created form and embed it in your site as you please.
Service: I have not experience any down time problem with the service so far. You can email, chat or talk to Jotform sale or support staff if you have any question building your form and application.
Technical Support: Technical support staff respond quickly and are very knowledgeable about any problems or troubleshooting you may encounter while building your forms and applications. There is big forum where you can get quick technical support and information.
I recommend you the services of jotform.com – so you should try it and see for yourself.