The apartment is stunning, comfortable, and beautifully furnished/decorated. 4 or 5 people could very comfortably fit in this apartment. The views are lovely, the shower is wonderful, and the location is either good or perfect, depending on what you're looking for. Note that the ferry stations are an easy ~20 minute walk away. This is actually a plus, since you’re close to nice green space on the water, and also just out of earshot of the mayhem that is the bar/restaurant scene of central Moda.
The construction noise across the street is not very loud, but it was present for most of my stay, with concrete mixers and heavy machinery running all day and late into the night. The bedroom is insulated from the noise, but this detracted from the tranquility of the living areas. Eventually I got used to the background droning and beeping. I may have had bad luck, since there was no noise at all for the last two days of my stay. Also, good luck finding anywhere in Istanbul that doesn't have construction work or another noise source nearby.
Quibbles aside, I would happily stay here again. I can see why that person who left the unhinged review wanted to move in long-term. Kadıköy itself makes for an interesting contrast with the European side, less chaotic (except on weekend nights), and ideal for the hedonistic traveler. It was fun getting to spend a few days here and not just popping over on a ferry to visit the famous food places all in one go. I took a ferry to somewhere else every single day, but that wasn’t a hardship—often the ferry itself was one of the most pleasant things I did in a day of sightseeing.