They begin with giving an unclear problem, for which there is upto 1 week to tackle (which of course a sincere candidate will give their full effort). I got a rejection after 3 weeks saying that (1)My paragraphs were long and not formatted (I had taken thoughtful care into avoiding exactly this, so I absolutely disagree) and (2) My metrics were weak. I've discussed my metrics with several PMs and by no means could anyone find the said metrics to be weak. Uber has created a messy process which asks a lot out of candidates upfront without a clear goal defined into what they're looking for. I'm highly disappointed by this lack of organization and thoughtlessness. I now understand how their drivers feel as purported in the news. Be human first, don't waste people's time with unclear questions.