I booked Cesim's place for a group of 8 people but 2 didn't make it so the apartment was extra spacious for us. The upper floor actually consists of two smaller flats, each with a bathroom but only one containing the kitchen. This situation was positive in some ways, and if we had any issue with the separate keys (as sometimes we'd split up), Cesim was able to help us with access.
The beds were of a good standard, though one of them (next to the kitchen area) was subject to direct sunlight because there was no curtain there. However, as we were visiting in winter there was darkness throughout the times we wanted to sleep. The bathrooms are a good size, especially in Room 8. The kitchen was adequate and there is a shop directly opposite where anything we needed was readily available.
The location is ideal as a launchpad for the Sultanahmet area and there are some decent and affordable cafes/restaurants on the same street. You should keep in mind that the street can be fairly noisy in the morning, and the other side can be noisy for other reasons (such as birds!). If you're a heavy sleeper then you'll have no problem.
Overall I was very pleased with the apartment and especially with Cesim's kind welcome and his help when I faced a few personal difficulties. Thank you!