I recently used ABnB to book Acapulco penthouse on 30th floor in the La Papala building on the main bay area near Costa Azul.
There are actually several of these condos available, so they are competitive, and on the off season, about $33 a night. It's a great deal for such a nice view.

That said, there are also scams on ABnB, like the monthly rent deal, that is strict cancelation oriented, and they advertise in one area, then after renting, send you the real address, in a different area (not beach front, not in the same area). In order to cancel without being charged, I had to contact ABnB directly, and had to get second level FRAUD support; the first guy that answered the phone could not help me and told me I'd be charged if I canceled the reservation.
I also had to look up ABnB customer service number on Goog, because I could not find it on their site!

That aside, I do like ABnB. Just watch your step...