It's in a fabulous spot just a few meters from Galata Tower in a very attractive area and in a great location to access public transport, shops, restaurants and is a short walk from Taksim Square.
Note though, some streets are very steep - if you struggle to walk, be aware, but this is generally true for that area.
The apartment is small if you have large luggage or there is a need for both beds, but if travelling light it is perfectly adequate, and I would recommend it.
There is reception service located next door, and Monica (who worked the position when we went) was fantastic - friendly, helpful, cannot praise her enough; knowing she was there made it less stressful to ask for travel advice or to ask about issues if they were to come up.
Great little apartment. Solid 4/5.