I suspect that some of the people claiming that Uber is going down hill are, well… not the best customers. That is, they might be total assholes. Uber tries to match 5 star cabs with 5 star customers. If you are a 4 star customer you are more likely to get a 4 star driver. The probability of getting a 4 star driver is higher today than it was a year ago, and a 4 star customer is more likely to get those drivers.

I've gotten the 5 for 5 thing a few times. I don't mind it, if it's going to be a 5 anyway.

I use Uber every day. I've had maybe two sub-par experiences with the black car—ever. A few iffy experiences with UberX but nothing bad.