I believe it is fairly accurate at estimating the ride time. The first time I took it though, I mistakenly thought it would take the same amount of time to get to my destination as Google Maps estimated since that is usually the case for Uber/Lyft.

So I was pretty annoyed after I got into the car and then realized that the route it selected was going through a bunch of hills and side streets that would take twice as long as the most direct route (via Google Maps) and there's nothing I could do to change that once the ride started.