I have driven for both in the past. Lyft has major advantages in my mind: 1. Tipping is allowed so you make more money that way. I don't think the fares are significantly different (maybe they are, I haven't compared). 2. You can cash out early. I was driving because I had just gotten a divorce and moved out and had extra expenses with getting into a new place, and frequently, being able to put $50-100 into my bank account after a night's work was the difference between solvency and insolvency.

Also, I've observed anecdotally that the Lyft passengers are nicer. I've talked with various people about why that is and there are various theories, but generally the idea is that it starts at the top. Uber has a history of dick moves and I think that reflects in the different clientele.