The place is exactly as it is described. For me It is a little bit dark, because it has a window that a bit shadowed by the trees and buildings nearby. The internet is acceptable, I used it for work, but I wish it would be better. Some things needed quick fix, but everything worked fine.
I stayed more in other apartments of these owners, they manage like 40+ apartments in several buildings nearby, and they were even better. I think it is good value for money, but keep in mind room sizes, steep stairs, average internet speed (but it worked, I didn't have any trouble). I found many grocery shops nearby, and Istiklal street is several minutes away, you can reach it on foot very quickly. If you use Istanbul buses, there is a bus stop nearby.
Some of property managers are always in touch 24h, so you can reach them with any question, they are kind and helpful.