Actually, the one thing that separates the OTAs is that their reviews are "verified" and are submitted by guests who have completed reservations at that property so they are supposed to be a lot better. If you compare this to Tripadvisor, anyone can submit a review so they have to deal with more fraud.
There are also several OTA's that decide to carry fewer hotels, and actually send an employee there undercover to check it out first before doing business with them. At the one I work at, we also look for hotels that cause lots of people to need to call customer service and remove them. We don't have as many hotels in as many places, but our target customers are the travelers who refuse to stay in subpar hotels.
