Random, unedited, unordered list of points: Great location, very clean apartment. Great air conditioning. The hosts were very accommodating and responsive. Pretty quiet inside the apartment considering how close it is to a party area (there was one night when some revelers in the same building carried on into the wee hours, but they weren't audible from the bedroom). My daughter and I went for long runs along the boardwalk every day (well, I jogged while her lazy 3 year old butt rode in the wagon), then to the beach. In the evenings we rented bikes and repeated the route. Can't speak from experience about the night life, but people seemed to be enjoying their drinks and music without getting hospital-drunk or violent. We weren't out later than about 10 or 11pm and maybe it's a different story after that, but we never felt particularly unsafe (all the same, practicing basic situational awareness and pickpocket defensiveness is still advised).
In fact, my wife accidentally left our minivan's side door wide open for several hours (she claims it was me, but I'm writing the review) and nothing was stolen or vandalized. Washer and dryer are coin-operated and generally available, but that's entirely dependant on the other guests. Parking is right out front and you have a dedicated spot. We were in and out quite a bit and never had to contend with squatters. Don't trust the weather report. One minute, there's a storm, the next minute it's sunny and gorgeous. Only weather-related complaint is that we visited during sargassum (seaweed) season, which makes going in the ocean a little bit like swimming in a salad (unless you go about 20 meters out). So, if that's a deal-breaker for you, it's probably best to search "Miami sargassum" before visiting to check water conditions before booking. All in all, we're very pleased with our experience and would book this accommodation again. Thanks for letting us stay!