Good things:
1. Bed is really comfortable and bed linen was amazing (and was smelling really good).
2. Easy communication with the host most of the time.
3. The host keeps material for washing clothes available, huge bottles of water (20L, so you can fill your small ones) and some basic cooking material (like olive oil). This makes life way easier there.
4. Having a living room with sofa and table is quite good and the fact that everyone on the apartment is a guest makes you feel more comfortable in it.
5. There is a lot of space to hang clothes to dry.
6. The kitchen is spacious.
7. Overall good price.
Bad things:
1. Extremely hilly, more then I could believe at first making it nearly impossible to leave without taxis (or sweating a lot and getting quite tired and losing a lot of time) and taxis are a real problem in Istanbul after Uber was banned.
2. There's a lot of glass in the room door so light comes in if the other room, the kitchen or the bathroom lights are on. Also the room curtain isn't good, a lot of light passes by it.
3. Sharing the trash bins can be tricky. There was one guy staying at the other room of the floor who trashed a lot of things and never took them out.
4. The bath space is really small and the water flux is weak.
I think the main point really was the transportation, if it wasn't for that I'd say the stay had been quite good.