I finally decided to try taking a Waymo a few weeks ago in SF. The cost wasn't much different than Lyft or Uber - it amy have even been slightly more expensive. I figured I'd try it for the novelty. Overall, it was pretty cool. You unlock the doors with the app and get inside, then a robot-voice tells you the ground rules. You can choose from some music playlists, or roll your own. The route I took was a nice, scenic, four miles through the mission area of the city. It handled everything pretty well, including some blind hills. It also seemed to comprehend pedestrians waving it to "go ahead" in crosswalks.
Being a resident of SF, of course I've heard about coning and some of the issues. I've seen a couple issues myself. One, where a way was in some sort of confused mode, sitting pretty far back in a left turn lane with its blinker on, but not moving. It stayed there for a while, and cars were going around it.
The second issue I saw was even worse. The car was confused and sort of sitting in place, but also moving around a bit. It would pull forward a few feet, back up the sam amount, and occasionally turn a little bit during the process. Still, nothing major, as it was on the side of a not very busy street. I've heard about them interfering with emergency vehicles on occasion. Not sure how serious this might turn out to be.
Overall, I think they have a lot of potential, especially in SF - which might not be a great test case for other cities.