I travel for work a lot and I'll use Uber to get to the airport. I've had some really incredible Uber experiences and some not so much.
My most recent one was an incredible one and I left my driver a 5-star review. About 20 mins after filing my review I got an email from Uber Support mentioning their Sixth Star Award program. They have partnered with American Express to award their top drivers from around the world.
The Uber Support email I got asked me to write as to why I thought my driver deserved the Sixth Star Award via a google docs link I was sent.
This is a pretty cool and unique thing I think Uber has going to reward their best drivers. I hope to see this get more publicity as something Uber does for their drivers.