OK, I have an Uber story - my first try at them. I stayed a couple of nights in Siloam hospital so had not driven there. Got free of the hospital in the early afternoon and said "let's try Uber". The app works a treat, the black Avanza with the correct number-plate arrives, we get in he gets back out onto Sunset Rd, goes 200 metres and stops just before the Pertamina opposite Carrefour.
He makes a phonecall (in a Java language) which gets heated. Turns out he doesn't have enough fuel to get to Ubud, nor does he have cash. Since we will be paying with credit card there is no question of us advancing cash. The phonecall is to his "boss" who owns the car and he wants cash to be sent by motorbike (such an Indonesian business model) but the boss is apparently short of cash or courier so its no-go. He says call another Uber which we tried - when this one turned up he also declined to go to Ubud. Now the app had already told them the destination, so why they accept jobs they can't do or don't want is a mystery. By now we had wasted 40 minutes so flagged down a blue taxi (not Bluebird) - the driver bargained a bit to 250,000 (double the 120,000 Uber quote) and off we went no hassles.
My partner says no way are we trying Ubuer again - although I would like to. I have used Go-jek in Ubud and like them.