I've never analyzed the data but sometimes the stars on the product seem to be slanted toward the high side when you read the actual reviews. Not that Amazon would stack the deck...
That may be natural though. I've had very few products that I was dissatisfied with. So if it is as it was advertised, good quality, and does what I want it to do, is that 5 stars. or maybe 4 or 3 because it should have been better than I expected it to be?