Location-wise is really good, Yenikapi and Marmmaray station is just behind but the area might seem a little bit sketchy for some tourists. Together with my partner we faced crazy things that happened outside of this apartment, drunk and drugged people screaming at night, we even experienced a shooting taking place outside around 5 am.
Daytime we never had any problems so just be careful when going out late at night. The apartment itself is decent, I wasn't expecting anything crazy but I have to admit I was quite disappointed with cleanliness, for me it was unacceptable, especially you should pay more attention to it due to pandemics. The walls are really thin, and if you got unlucky you might have to deal with problematic neighbors.
I have to admit, contact with the owner is great and he is really helpful.