At least going by the r/selfdriving cars subreddit, it seems like Cruise cars get into a lot more 'incidents' than Waymo cars. Especially getting randomly stuck because they don't know what to do.
One of the articles about this past weekend's Cruise traffic jams mentioned the company blamed a flakey cell phone signal as the root cause. Now why would having perfect access to cell networks be required to keep the car driving... I suspect because Cruise is relying much more heavily on remote human drivers. It would not surprise me to find out Cruise is just a big scam and the self driving algorithm fails so often the cars are basically just remote piloted taxis.
fwiw, my personal experience testing both has been that Waymo's vehicles are noticeably better at driving, and also drive more aggressively. It's to the point where sitting in a Waymo vehicle is unremarkable and I don't even pay attention to its driving, while Cruise still typically has at least 2 "that wasn't great" moments per ride.