TLDR: I stayed at Guy's place for two months in fall 2021. The place has potential, but it needs some improvements and an updated listing before it is suitable for Airbnb IMO. Guy was also nice and easy to communicate with throughout.
Cleanliness: When I first got to the apartment, the floors were visibly dirty, while the much of cookware and oven were covered with built-up grease. There was also black mold behind the sink at the base of the backsplash, and used insect glue traps inside the kitchen cabinets. Once I told Guy, he was very helpful—he apologized and booked a cleaning service which came on the 3rd day of my stay, and agreed to give me a 10% discount on the reservation.
Pests: About a week in, I started seeing German cockroaches in the kitchen and bathroom. Guy paid for for some poison baits which I bought and set myself, since the building's exterminator wasn't scheduled to come for a few weeks. I also began taking out the trash and inspecting the kitchen floor for food scraps daily. Luckily, I stopped seeing roaches after that, but then after another week or so, I spotted a mouse in the living room. This was undoubtedly the result of the various cracks and small holes around the poorly-maintained steam pipes and baseboards. Guy reimbursed me for some mouse traps, which failed to catch any. In total, I spotted roaches about 4-5 times and mice about 3-4 times during the 2 months.
Other maintenance issues: There was also a natural gas leak in the apartment about 2 weeks into the stay which left us unable to cook for 3 days while the stove's gas line was replaced. Guy was understanding and reimbursed us for the extra cost of eating out.
Noise: The walls in the building are very thin and you can hear loud footsteps and kids' voices from the upstairs and side neighbors, as well as from the lobby. I could even hear the morning alarm of the neighbor who lives directly above the bedroom. Of course, this is out of Guy's control, but this should have been noted in the listing information at some point either before or after booking.
Location: Being close to Prospect Park was awesome and the 2/5 at Sterling St. station is very convenient. However, for people who plan to cook a lot this may not be the best option since the nearest supermarket is an 11 minute walk, as the local Associated closed last summer.