We have stayed at a number of Airbnb accommodations recently. We feel the $500 additional 'refundable deposit is unreasonable and should have been mentioned prior to requesting the booking.
When renting a 4 person accommodation it is not unreasonable to expect 2 keys enabling access for parties. We were disappointed with the overall size of the rental and also tiny bathroom which is barely big enough for 4 people to share.
The one redeeming feature we found was the swimming pool, when the weather was ok to use it.
Only our opinions and others may have a different outlook on this establishment.