Location of apartments is good, at the center, near Istiklal street and Taxim square. There are a lot of cafes, bars and shops. But be prepared for noise due to the proximity of all these facilities. We slept in earplugs and it was not a problem for us.
Not the cleanest towels and bed sheets. Mattress is very soft, I took a very strong backache after 3-4 days sleeping on it. Internet connection isn't stable (most part of time it was good, about 20-30 Mbps, but sometimes the speed dropped until 5-6 Mbps).
The hood constantly smelled of tobacco smoke.
If you have heavy baggage, be ready to climb very steep stairs with them.
Host Ertan was very polite, helped us with transfer at 4 AM, helped with any questions quickly.