Most builders believe they understand the feelings of customers, employees and vendors through sporadic feedback from sales, management or construction personnel. But this information typically is flawed with personal agendas or small sample sizes. Surveying each constituency against specific success factors gathers a true measurement.
I would outsource these surveys. Organizations that specialize in them have validated them and provide data you can trust.
Create an emphasis and business focus on the information being obtained. Many builders look only at the consolidated "will refer" question. That's important, but as a stand-alone piece of information, it can be misleading.
The key to the survey is in understanding it line by line as seen through each respondent's eyes. Your entire business plan can be constructed by focusing on the data received through each survey component. Look at these surveys as a way to develop a formal process of ensuring satisfaction throughout your organization.