We did not end up staying overnight in this accommodation because we only needed a space to rest for a few hours before our bus ride out of Istanbul but what we can say is that the host was very friendly and helpful :) They actually took the time to advise us on how to book our bus tickets and get to the bus station. Very kind and accommodating people.
The location is quite good. We were able to walk to the Grand Bazaar for shopping and there are also many food places within easy walking distance from the apartment. If you’re wanting to visit the tourist attractions you could take the T1 tram from the Grand Bazaar to Sultanahmed.