Are robot mowers good on slopes?

It depends heavily on drivetrain. All-wheel-drive models like the Mammotion LUBA 3 AWD (rated to 80% slope) and the Worx Landroid Vision Cloud 4WD (rated to 84%) are the consensus picks for hilly yards. Front-wheel-drive models in r/worxlandroid threads are reported to struggle on dewy grass and steeper grades.