I spent one month in this apartment and it has everything you need and even more. It's easy to reach Erhan through what's app anytime.
Istanbul weather this March was a bit cold but Erhan apt. has a special heating system, so it was really comfortable inside.
The internet is really fast without any issues, if you're working online, don't hesitate to book it.
It's hard to find good restaurant in Istanbul but Erhan has a lot of recommendations, I checked them and most of them are good enough.