It's really cool invention for lazy people or for these who want to create smart home.
I personally suggest to buy one Xiaomi robot vacuum cleaners, you can get it for less than $300. Probably Xiaomi now offering one of the best robots in the market right new for very good price. Sadly I can't have robot vacuum cleaner at my home because it wouldn't able to pass the doorsteps - it's just too high for him. So, I have to clean my home in old fashionated way...
Xiomi and Roomba are definitely the most famous ones. They are definitely one of the best robot vacuums available at the market, but people don't see other decent names. Such brands as Neato, Ecovacs or Vava are worth trying too. Various sites like
https://robotsnavigator.com/ state that you should select the robot vacuum according to your house flooring. Indeed there are so-called universal vacuum cleaners but from my experience, you should focus on a particular one.
I agree Roomba and Xiaomi are more reputable brands you can't go wrong with them just choose whatever fits your needs and your budget you can find comparisons between these robots in this youtube channel