I have heard nothing but nightmares. You can't even leave reviews for guests, so you have no idea who you are getting. Unless you are hosting in a commercial hotel, stay far far away!
The platform is horrible to use and customer service is non-existent. I don't think there customer service ever intended to deal with small-time operators - mainly the commercial and more established lodging chains who can usually enforce rules on their own. Good luck trying to have booking.com tell someone they need to leave for breaking the rules.
I was on booking.com as well as airbnb and vrbo. I feel like the booking.com guests were expecting more of a "hotel" experience rather than a homestay / house setting. I did also get a lot of foreign guests who seemed a bit shocked there was no breakfast..
We have used it here on the east coast where we rent out two rooms from within our home and have gotten mostly European guests who have been quite nice. I think it depends on your area and what type of "typical" guests you might get in your area. But all in all compared to the airbnb platform the system is not as easy to use but it fills some of our empty nights.
Be very careful that if you ever host on booking.com and for some reason you made a mistake or cannot host, YOU will be responsible for find guests new accommodations.