The place is actually a room in a small private hotel that is located just a few blocks from Sultanahmet square and Grand Bazaar.
The room has everything one would need for a comfortable stay, plus, there is a sauna in the hotel that guests have access to. Ahmed or someone else is at the reception 24/7 to help you find a good restaurant for dinner, call a taxi to airport or just treat you with Turkish tea and sweets.
Check-in and check-out were flawless.
I would definitely recommend this place, and I would choose it for my next travel to Istanbul.