Full, disclosure: I work at Google
but... I rode in a Waymo and a Cruise in the same week recently, and terrifying is exactly how I would describe the Cruise ride.
It often couldn't find it's lane and kept making abrupt swerves and corrections in the road. It would hesitate all the time, then seem to try to make it for it by gunning it forward when it made up its mind. Then five our so Cruises at an intersection near Market St couldn't figure out how to get through the light more than one car at a time, backing the whole street up. People were pissed. My friend who had the Cruise app thought it was normal and kind of fun :/
The Waymo ride, on the other had, was kind of boring. The worst part was it circled the block picking me up because it didn't see a good spot to stop right away (and I think I moved a bit from the pin). Other than that it was a very smooth ride, it showed me on a screen where all other cars and pedestrians it knew of were, it gave pedestrians enough room, it even handled a two-lane street where there were stopped cars blocking each way and it had to zig-zag across the double yellow, and yield to cars from the other direction doing the same.
I will not be riding in a Cruise again for a while, and I'm kind of scared to be on the street with them.