Pros
Fulfilling work. Focused and hard working culture. Transparent management. Refreshing experience. Fun and warm colleagues. = I've never been happier. And I previously worked at the last two hottest startups in Silicon Valley for the last few years.
Cons
There is nothing that I would specifically consider a "con" of working at Uber. If anything, I'd suggest to management that they hire an executive chef and kitchen staff and build out a full kitchen that serves gourmet breakfast, lunch and dinner. I know this sounds a bit ridiculous, but food is the centerpiece of hacker culture in Silicon Valley, and was central to creating the "magic" at the last two companies I worked at. I think it'd go a long way in attracking and retaining talent. It does at Google, Facebook, Dropbox and Palantir ;)