I don't know whether this is a real difference or not, but Lyft "feels" like a much nicer company than Uber. I'm not thrilled about Lyft's rampant hipster-branding, but Uber seems like a company run by pricks. Maybe it's just because they're the underdog, but I'm really rooting for Lyft.
I recently interviewed with Uber in Asia, spoke to a half dozen people there right up to the head of the region and many Americans who have been with the company for years, and I did not get the job (so, clearly not biased towards the company).
Here's my one data point: they were all really nice, professional, competent people I'd actually want to work with. When I say nice, I don't mean polite, but trustworthy and well intentioned.
They are working very hard to cope with the massive growth of their app, trying to figure out how to manage 200 offices in parallel with tiny teams whilst keeping the same quality standards and avoiding unsavoury incidents that come when you hire a large number of people in many locations (imagine what would happen if there was a rape or robbery attempt by an Uber driver). They are under extreme press scrutiny and large amounts of negative PR globally, because they are hitting some of the best organised, most entrenched oligopolies.
Psychologically, it felt like there was a strong sense of family and purpose, that I haven't really seen since I left commodities trading (whose companies are family owned businesses where long careers are common). They were proud of what they were building, genuinely appreciating the value added to the community by their work. The place also felt meritocratic, with people getting expanded responsibility rapidly after proving themselves (based on the career path of the long timers I talked to - could be survivorship bias).
Naturally, I poked a bit towards the "unethical" side of things, suggesting a couple of things as feelers for how they would react. The reaction was overwhelmingly negative - it seems that "dirty tricks" are not looked well in Uber in 2015 at least, fair competition is the name of the game.
So, they impressed me enough as people (after impressing me as a service) that here I am putting up a positive word on HN. I suspect much of the negative press is "black" PR from competitors and threatened interest groups.