After a brief online application I was sent the dreaded excel test, which I completed just in time, and to a high enough standard that I had a follow up skype interview, and then subsequently an interview with the Operations manager in their office, which was the end of the road for me.
The excel test requires you to work efficiently, but isn't especially difficult. The phone interview was very general, and the interview in person quite full on. They made a big deal about being rule breakers and looking for "fast and dirty" solutions to problems. Also appreciated anecdotes of being extremely busy with work, as they clearly expect their staff to be completely dedicated to uber. They made it very clear that you were expected to work quite extreme hours.
Among others asked questions like: What's the biggest risk you've taken, what have you learnt recently, what's the biggest rule you've broken, what's your biggest failure etc. Also needed demonstrations of sales/persuasive ability which I think is where I fell short.