I've only taken them twice but I was surprised by how smooth it was. They're pretty defensive drivers, which is what you want, but were still able to navigate some tricky stop signs (e.g. a biker biking along stopped cars, pedestrians trying to cross in both directions) without getting totally paralyzed.
It's a really uncanny feeling when it pulls out into traffic for the first time and the car is driving itself. I have a Tesla, so I've played around with autopilot, but being in the back seat and not being responsible for the car at all is a crazy feeling. Legitimately one of the most "oh my god I'm living in the future moments" I've experienced in recent memory.
Pick up and drop offs get snapped to specific areas so I had to walk ~1.5 blocks on either end which wasn't a big deal for me, but could see how that might be annoying/difficult for others.