This is an historic building, so be prepared to walk up 7-8 steps to get to the elevator. Using the elevator requires you to open a large heavy door to get into the elevator and to exit it. The unit is on the third floor, so if you have any ambulatory issues, be aware that the unit is most easily accessed via several flights of stairs.
The other issue to be aware of is the street noise. The windows are thin, and the unit faces the street, so you will hear garbage trucks, delivery trucks, people talking, cars honking, etc. If you are sensitive to noise, then be sure to bring good earplugs and a white noise machine. Also, bring an eye mask, since the glorious Florida sun floods the room in the morning.
It was a bit strange to arrive to find plastic wrapped bundles of linens and towels on the bare bed. However, it was nice to know that everything was clean and fresh from the cleaners. Be prepared to make up the bed yourself. It was a nice touch to provide a beach towel!
The apartment is serviceable and priced fairly. There are aspects that are run-down (like the shelf in the bathroom is heavily damaged, several of the slats on the blinds are broken, etc), but it's a spacious studio, and it was clean. It's not lux, but it's inexpensive and the location is fantastic. The property manager was responsive and easy to contact. Overall, it was a good place to stay while spending a week in South Beach.