Had a lovely stay at Rosario's place! The location is great for the price - you can easily get around Waikiki / Ala Moana / to other points of interest via bus, or car if you rent one (we did not), without having to be near the crowds in the thick of Waikiki. Also some good coffee and restaurants within a few blocks.
The unit/building are older but the apt is well maintained and very tidy, though we did get a few bugs in bathroom/kitchen as we anticipated we might from the reviews/listing and being on an island. Be prepared to use the provided Raid, and if you get super squeamish from bugs maybe this isn't the place for you!
Building is mostly other Airbnb guests who can get a little loud/annoying in the elevators or hallways, but that's par for the course for Waikiki I think.
Rosario was super responsive when we got confused checking in / needed more bug spray and also very kindly let us leave our bags for the day after we checked out, so we could enjoy more of Honolulu before our flight home.