Highly recommend.
The building is full of art and color and hand crafted shelves and tiles. Mustafa does most of this himself.
The room is on the ground floor, so it was cooler in the 90F weather, especially with the screened windows open. A lot of activity on the street into the night (kids playing, cats meowing, and people chatting), so if you're not used to noise I suggest bringing some earplugs. But this wasn't an issue for me.
If you want some good coffee, I went to Fig Tree on those secret stairs or if you walk north up Vodina Cd. there are a few bakeries for ekmek and places for dürüm and pide. There are also a few ATMs up that way.
The terrace is as lovely as the photos and I spent a lot of time up there reading and drinking tea.
A final note is about Mustafa who is now my best friend I think. He showed me all around Eminönoü and Sultanahmet. It was a really amazing way to begin my trip.
Staying at this place is much like being in a building full of neighbors you have known for 30 years. People pop in and out and check on you and invite you up for tea, but they also respect you if you just want to relax.
Loved staying here!