I had a nice stay in Karem's place in Istanbul. The apartment is very close to many attraction and a great transit location. He communicated almost instantly for what we needed. Although I never met him, the people at the front desk were super helpful and friendly. The apartment was clean.
Overall Karem's place is more like a small hotel as he has staff on site even for cleaning and stuff. The sofa bed in the room was not very comfortable for the third person to sleep however the cleaning ladies made a separate bed in the corner from the second night which was comfortable. The only thing I would change if I were him was the heavy smell of the strong detergents or chemical bleaches used for cleaning.
Overall if you are looking for a hotel like accomodation you can definitely have a nice stay there.