Cheap but good robo-vacuum

We had a $900 robot vacuum cleaner, but our elderly cat mistook it for a litterbox and peed on it, rendering it inoperable. After she died, I bought this cheap Lefant Robot Vacuum Cleaner, and it works as well as the costly one did. It comes with a smartphone app, but I don’t use it. I just push the button and it shoots out of the charging port and starts rolling around sucking up dirt. When the batteries are low it finds its way back to the charger. — MF