We are into our 3rd month of our European Adventure and all of our accommodations have been booked with either Booking.com or Airbnb. Our youngest son referred us to Airbnb which he uses extensively and highly recommends. I would estimate that at least 90% of our bookings this trip have been with Booking.com. We have had one minor incident where the host did not honour a reservation we completed with Booking.com as a result of a double booking through anther site. Booking.com resolved the issue within days to our total satisfaction by offering us a generous credit that they applied directly to our credit card. We have been very satisfied with our bookings through Booking.com but unfortunately not quite as satisfied with Airbnb. Not sure why but maybe it has something to do with the billing arrangements. Booking.com charges the host a fee which I am told is between 15-20% of the billing. Airbnb bills the client upon booking and from our experience it appears to be approximately 12%. We have been told that Booking.com has strict rules when it comes to accepting a host and I am not sure if Airbnb has the same guidelines. For example, booking will not accept a host if their accommodation is within so many meters of one of their existing clients. Bookings reviews are a "one time" format meaning that you have one opportunity to post a review with not replies or rebuttals by either host or client. It seems with Airbnb, the host always has the final say but I could be wrong. Airbnb encourages you to settle any dispute or problem you have directly with the host. Booking.com appears to take more of a "hands on" approach. Also, try contacting Airbnb! It is next to impossible!!
In any event, I think the client is basically left to due their due diligence in gathering all the information they can about their accommodation provider outside the booking site to try to obtain a totally and honest opinion and review of the property. Airbnb tends to specialize more in apartments where Booking deals with hotels and guest houses, although they do have some apartments. From our experience, Airbnb has a better selection of apartments in the bigger centers around the globe. We always try to obtain a review from TripAdvisor before finalizing a booking with any site but you cannot obtain a review on an individual apartment unit. Therefore, you have to rely totally on the reviews you read on the site and I really question the authenticity on many of the reviews we have read. I am not sure what sort of screening process these websites have in place to police the accuracy and source of the review but there definitely is room for some major improvement.
But to be fair to these sites, not everybody share the same opinion therefore it becomes an impossible task to try to provide a review that will accurately describe everybody's wants and needs. We will continue to use both Booking.com & Airbnb but remember... "BUYER BEWARE, CAVEAT EMPTOR".