Actually most rides I've had are 5s. I start at 5, and as I notice shortcomings, the rating starts to fall. I would say 70% of the time it's a 5 star ride.

So far I've used Uber in

-Tucson
-Phoenix/Scottsdale
-Los Angeles
-Wilmington
-Berkeley/San Francisco
-Rome
-London
-Vienna

Tucson is the absolute worst. I don't think trucks should ever be considered for Uber unless they specifically create a truck service, you are going to an offroad destination/event or the truck is spotless (or a Lincoln Mark/GMC Sierra Denali).

Drivers need to be specifically trained to follow the pin for pickup and dropoff. At the same time, users need to understand that the pin does not always accurately match their GPS location, or that their GPS location may not reflect where they are (especially if cell service is weak). I've never had a problem telling the driver to pick me up at the pin after actually verifying the pin has located ME correctly.

Being customer-focused is what Uber is about. When drivers fall short in any of the areas I mentioned earlier, their rating suffers. I'm not reporting them, I'm just giving them a reminder that things could be better.