From Jason Fried at 37signals:
It was fine – I couldn’t imagine it to be better, but was it TRULY EXCEPTIONAL? No. That doesn’t fit. So does that make it a 6 or 7? No, it was better than that… But… So…?
Surveys are great tools for finding out what your customers think about your product. But watch how you construct them and what language you use. If the customer has to struggle over a survey choice, they’ll probably just drop it without ever finishing it.