We've used air n b many times, they hold the money until you check in and only release it to the owner/renter if there are no problems the day after you arrive.
An issue we did encounter was we had booked an apartment in Paris for the euros last year, we booked around a year in advance as we knew places would book up fast, around 5 months before our arrival they said they hadn't realised it was the euros and wanted double the rental fee (we had already paid months previous) we refused and they cancelled our booking.
With air n b the owners can cancel bookings with no penalty to them.
We've used them a few times since so it hasn't put us off.