What can be said about my experience. It was amazing. Alev is super chill and interesting, a former journalist that now runs an amazing (and expanding) set of yoga studios.
I felt as if I was staying with a friend I had known for years. No stress, no pressure, didn't at all feel like I was in a foreign space.
The place is awesome. There is a bit of an uphill trek when leaving the place, and there is no elevator, but the charm of the space makes you forget all about that. One thing to keep in mind though, as others have said, the loft ceiling is quite low. I hit my head many a time. The secret is to stay towards the middle of the space, and you should be okay - for the most part.
The location is brilliant, just about a 10 minute stroll from Taxim Square, but the immediate area has so much more charm than what you'd find at the square. It has loads of hip places to eat, so many antique shops, and all sorts of interesting places you'll find exploring the area.
The location is close to the M2, T1, and coach that will take you to and from the airport.
I'm sure I'll be back in the magical city, and Alev's place would definitely be where I'd look to stay.