I read an interview of the founder of roborock a long time ago and it was clear at that time that he had so much attention to detail that the product turned out to be superior. These days roborock behaves like it has definitely "solved" the robot vacuum problem and has transitioned to researching hardware for self-driving cars. I cannot yet decide if that's a brilliant strategy or a monumental waste of money that will hinder their continued development of robot vacuums.