Free version is probably fine for most user needs. It is helpful to have the customization templates. It is extremely easy to set up and collect data. I have found other uses beyond a typical interview survey. For example, I have to collect yearly updates from organizations I work with. Instead of having them send back individual responses via email, I direct them to a survey monkey page with the questions. Their answers are automatically entered into one spreadsheet and the program keeps track of who has responded.
Sometimes it can be a bit clunky to format the questions if you want to do something that is outside of the template.
Try it, you will like it. There is a FREE version with plenty of features.
Easy method of data collection for more things than formal interview surveys.