I ignore the Chinese because it is difficult to get reliable English information. Apart from those, these are the only level 3 systems available, and level 3 is the most advanced system that private individuals can currently get their hands on. Have I missed any?

It's not a benchmark, but there is a youtube channel (Out of Spec) which tests these systems, and I think they also say Mercedes are the best in their "Hogback challenge".

https://www.youtube.com/watch?v=xK3NcHSH49Q&list=PLVa4b_Vn4g...

Worth checking out, many cars are very bad.

Don't forget Blue Cruise from Ford.