Great clean apartment with wonderful views. I think it's perfect for 6, with 3 full bedroom and 2 T&B's. Bathrooms are a bit small, but definitely workable, not something that bothered our stay. The bathroom tiles can be a bit slippery though, so I would be careful with that. There are some toiletries available but we ended up buying our own during one of our first grocery runs. Guests are going to need to buy their stock of bottled water from a shop anyway, might as well buy toiletries and kitchen staples if you plan on cooking, they're certainly cheap enough in most Istanbul shops.
I would not be concerned with privacy even with the curtains open as the windows are made of very effective one way glass. Views are amazing, but that means other people like to enjoy them too at the park just underneath the flat. The people staying at the outermost room are going to be able to hear outside noise, but personally it was not loud enough to bother my sleep.
Location was great just above Tophane tram station. Going out was easy enough in the mornings but walking back up could be a challenge if you have children or elderly guests. Personally, we just walked going out in the morning but booked taxis through BiTaksi to come back home after dinner. Google maps gives some weird walking directions sometimes, but ask Ismet of the best routes when you check in. If you're walking, I recommend taking the path through the park. Quieter, nicer view, with a friendlier steepness than the roads. Alternatively there are stairs of maybe 120~150 short steps about 50 meters east of the flat that takes you to ground level right across galataport and near Tophane station. There was always a cruise ship docked in Galataport during our entire stay but the area never felt more crowded or busier than any of the other main areas in Istanbul.
Separate airconditioning in each of the 3 rooms and one for the living room/kitchen all worked great. Hot water was also always sufficient for 5 of us. Free daily cleaning and dishwashing plus laundry services were all very nice perks too. Ismet was very easy to talk to and easy to coordinate with. Definitely one of the best AirBnb properties we've stayed in.