I just returned from a vacation where I used booking.com and what a nightmare. The hotel we booked through their "verified" system turned out to be a bait and switch scam - the rooms were not as pictured, facilities it listed as featured were non existent, rooms not soundproof, no AC, dirt everywhere, and the list goes on.
The worst part is when we tried to bring it to Booking.com's attention, their email support team shamed us into not having done more research even though their own website listed this hotel as being very good. When a company attacks its customers for placing their trust in it, there's something wrong with the company.
Too long; didn't read: we stayed in a way over priced dingy hotel and when we complained booking.com blamed us for having booked based on their recommendations.