We enjoyed our stay a lot- it is extremely nice apartment! I think it is much bigger then the pictures suggest, and nicer as well :) We found it comfortable to stay with 6 adults. You get big living room to hang out, full-functioning kitchen, and an independent bathroom for each bedroom, which was very handy for our stay with an extended family.
The place is a minute walking from Galata Tower on a quite street. The neighborhood is quite touristic, but very centrally located - it was quite nice to walk everywhere in Istanbul from it. And there are nice locally-ish streets around, you just should know a corner to turn.
We came to visit with an infant, and appreciated the fact that baby crib is available. Also the apartment is on the first floor (1 staircase), so it was quite doable to get up and down with a pram. Neighborhood is quite hilly, so some streets are actually stairs - beware and check the map, but nothing critical.
Unfortunately, there were three blackouts (no lights, no hot water) during our week-long stay each taking the municipality hours to resolve. Maybe we just got unlucky, because of stormy weather.