Positives:
1 - Location. It's unbeatable in terms of access to taxis, metro, funicular, trams, restaurants, cafes, sweet shops, you-name-it.
2- The apartment is very pretty. It's in an old "passage building", with tons of charm and vibe.
3 - The host was super friendly, picked us up a little bit away from where we were supposed to meet, helped us with our luggage, etc.
Negatives:
1 - We were specifically looking for apartments with elevator access, and this one promised it - but didn't deliver fully. The elevator reached only till the 5th floor, and from there, we had to use 1 set of stairs to climb up, walk a bit, and then another set of stairs to climb down. If we had known this in advance, we would have picked another apartment.
2 - The apartment ran out of water one morning, and we had no water till 13:00 hrs. This could be as much of an Istanbul problem as an apartment specific problem. It's hard to say. On the same day, we were visiting some other restaurant in some other neighborhood, and they had no water as well. But the MADO next to the apartment (whose bathroom I had to use), had water. So, this is a bit of a toss-up.
3 - The internet speed was just 1 MBPS.