Quantifying feedback. Usually we are aware if there are any issues but it's always a good way to quantify that feedback and find out if there are any real issues that need attention or just squeaky wheels.
Flexibility. There is a lot you can do with SurveyMonkey, be it in how you can ask questions, the format or how you can analyze the data.
Reuse great surveys. If you have a format that you like, you can easily copy it to tweak and use again. Love this feature!
Always better to get actual feedback than to just rely on what you observe from a situation or think you know about your market.
It takes a little bit of work, so planning and coordination are a part of the process. Make sure there is a business case for each question, rather than just asking something that would be nice to know.