I stayed here for 5 nights and I really enjoyed it! The location is fantastic: 5 minute walk to Galata Tower, and a 5 minute walk to Galata Bridge. The room is exactly how it is pictured, and it has everything you need (including 2 bottles of water, tea, coffee, and a pot to heat water). I also really enjoyed the massive window with good views. Although I didn't meet him in person, Cüneyt is a very kind and helpful host.
I saw some reviews mention the lack of hot water, but I didn't have this problem at all.
If I return to Istanbul, I will definitely stay here again!