We had a one month stay at Isa's apartment. We were able to communicate well using AirBnB/Whatsapp. The check in process went smoothly with his friend who speaks good English.
The biggest advantage of the place is it's location. There's several cafes and stores at a short walking distance also many restaurant options for food delivery. It's about a 3 min walk downhill to the Tophane tram station where you can take the tram to the sights and a 10 min walk up to Taksim. The apartment is on the ground floor of the building. The windows facing the street are protected with bars and guarded by a cute stray cat who loves to lounge on top of the outside A/C unit. There's a parking lot facing the building where you can park your car. Both the living room and the bedroom are quite spacious equipped with comfortable furniture. It should be noted that the building is on a steep hill facing a main road. If you're a light sleeper you will benefit from using earplugs. The curtains in the bedroom block the sun quite well. The kitchen comes with pots, pans and silverware for those who wish to cook.
A couple of potential cons that I would want to know before booking:
Since I work remotely I like to have a dedicated workspace which this had listed as having, however, there is no desk or anything similar so I had to make due using the ironing board.
Also, the AC works, however it is insufficient to cool the whole apartment. The bedroom is much warmer compared to the living room despite having a ceiling fan.
Overall it's a nice place to stay in Istanbul especially for those wishing to stay in the Beyoğlu area.