We were met by assistant on time when we arrived. Mersin wasn't himself there, but he was constantly in touch over internet and very responsive to our requests.
Apartment is nicely furnished and well stocked with kitchenware, soaps and other necessary stuff. White style decor makes you feel like having more space. Everything was fairly new and very clean and tidy. Beds were soft and comfy. The bathroom has all things you need, except toothbrush and paste. Washing machine in bathroom is very handy. The grocery store is right at the corner. But I would recommend going down towards Tophane turn left and there is a minimarket opposite to a small park, there you'll have a wider choice.
About the neighborhood itself. It's very close to Galata tower and Istiklal street. Tophane train station is 2 minutes walk from apartment. You can also reach Sishane metro station in 10 minutes walk. But I would say that this place is for younger crowd. Stone paved streets around can be quite steep and can require some stamina to walk, especially towards Istiklal. The streets there could be cleaner, sometimes there are small bits of trash laying around.
Liked our stay in apartment a lot. I think it's one of the best offers in that neighborhood and I would definitely stay again there.