In a usual "city-approved" taxis you get crazy behaviour, parking in dangerous places, speeding, etc. Try complaining and you'll learn that drivers only rent the communication equipment - the company is not responsible for what they do.
In Uber, I got a dangerous driver only once (where "dangerous" meant tailgating, but nothing really bad). He got 3 stars and a comment. I got 2 emails following up on the situation and Uber's assurance that the driver has been talked to.
So yes, I'd much rather share the road with an Uber/Lyft driver, because I know the feedback actually works in that case. There's another case of what insurance they have of course... but that's another topic about actually using the service.
Yeah, the feedback system seems to be a cool idea. In case of Uber though, keep in mind that the driver will get fired if their average rating drops to ~4.6 stars. That 3 you left there? Probably had a really big impact on him.
But, to be honest, a crappy driver is a crappy driver. Taxi drivers just seem to be worse in my personal experience.