I've had ethical qualms about Uber for a long time, but I've always gotten good service.
Unfortunately, I had a Lyft experience that really turned me off. They matched me with a driver who was 5-10 minutes away (I believe he was at Millbrae BART). He messaged to ask where I was going, and then once I responded he moved his car slightly farther away from me, and then parked it. We waited ~10 mins. He was unable or unwilling to cancel the ride that he wouldn't give us, wouldn't respond back to me, and Lyft customer support didn't seem to care.
It was infuriating. Either do a better job matching, lower the penalties for drivers canceling, or enforce the same/worse penalties for refusing to pick up. If the driver's best course of action is to ignore your customer, you have a problem. Maybe that's changed since then, but it's not necessarily a good thing for consumers that drivers say they prefer Lyft.
I use both, infrequently, and rationalize it because my rides are being subsidized by investors. I think short of dramatic leadership changes, Uber can't fix their corruption. I'm hoping they run out of investors willing to give them cash, or they're disrupted by something even better. As long as they have the best product, I think they'll continue to grow.