This place is okay for staying short terms but not suitable for the long-term at all. Location is fine for tourists since it's located right near the subway and in close range to the main attraction. If you're staying long-term I'd picked more calm areas since Taksim square is very crowded and loud.
Apart from that for the 30 days stay, we faced these issues:
1. Internet almost doesn't exist in this place. Although I specifically told the host that we need to work and they said the Internet is average for the city. It's true Istanbul usually has not a fast speed Internet but the issue in this apartment doesn't have anything to do with it. The problem is that they have 8 apartment for 1 router which located on the 2nd floor and the signal is very weak. Wi-Fi repeaters are not working at all. So you constantly experiencing huge ping and disconnects. If you are planning to work I strongly recommend considering another place.
2. The place has a lot of black molds all over the apartment. You probably can get along with it but in the long-term it's unhealthy.
3. The place has only one set of linen for the whole stay so in the end, you'll be sleeping on dirty ones. Also it quite dusty especially if you open the windows from time to time.
Other issues not related to long-term stay:
1. When we arrived it was really hard to find the place and the host didn't get us any instruction and were late so I had to find some construction workers and ask them if they know about Airbnb and go back and forth.
2. Apartment has very steep stairs between the ground floor and the elevator so if you have problems with your legs or you have a huge suitcase you'll be having a hard time.
3. One day the building changed the locks downstairs and we couldn't get inside the apartment which was a frustrating experience.
Apart from that it's a small apartment but has everything you need for a short-term stay and it's quite cheap. Location is very well for tourism, it has a lot of cafes around so there won't be a problem with food. It also have washing machine but it drys not very good.