Communication from the host was great from the beginning. We booked last minute for 4 people for one night, and the value for money was great.
The sofas are pushed together to make a second double bed - comfy enough for one night. The kitchen window didn't have a curtain, but we fashioned one so it wasn't a problem.
Unfortunately the drains were quite smelly; as long as the bathroom door was shut this was okay.
Air conditioning worked well in both rooms and shower also had hot water working well.
Bring your own bags upstairs! The person who brought ours up was quite forceful and wanted an unreasonable amount of money. It was uncomfortable and we waited a while for him to leave.
Bring mosquito spray! Lots in the apartment.
Fantastic location! Right near the Galata Tower and great for restaurants and bars. Lovely area of Istanbul and worth visiting.
Overall, apartment would be perfect for 2, a bit of a squeeze for 4 but it's doable for one night or two.