Firat is a great host! His English is perfect, and he is available and responsive via multiple channels.
The unit itself matches and exceeds the description. It has everything one needs in a daily life. We spent a month in Firat's unit, and didn't fall short of anything during that period.
If you are traveling in the summer months - worry not, as Firat's unit has a pretty powerful aircon (which is a rarity in Istanbul). This was a life saver for us.
The block has secure entrance, a lift, and the unit has several locks (if that is something that concerns you).
Location is considered as one of the central locations in Istanbul. It takes some uphill walk to reach public transport, but that is the case with almost anywhere in Istanbul.
Food and drink outlets are in abundance in the area. The seaside (and the outlets there) is within walking distance. Ordering food home is also another option.
Cevahir shopping centre (quite a big one) is within 15 minutes of walk.