This is a compact, stylish and cosy apartment. The interior is lovely, with wooden floors and brick and plaster walls, high ceilings, and plenty of natural light. There's a small kitchen with (limited) cooking facilities against one wall.
In terms of location, it's very convenient: right in the centre of Beyoğlu, only a couple of minutes walk from either the metro (Şişhane, M2 line) or the tram (Tophane, T1 line). You can get to or from Atatürk airport by metro in under an hour. The Sultanahmet (Blue) Mosque, Aya Sofya, and Tophane Palace are a few stops on the tram. İstiklal Street is ten minutes' walk away. There are plenty of places to eat and shop, including two good vegan restaurants in the next street.
Downsides: the area is all very steep hills, so be prepared for a lot of climbing and descending. The bathroom/toilet is separated from the living area only by a frosted glass door, so if you're sharing, make sure you're comfortable with each other!