Really enjoyed our stay at Axel's place. He and his friends were always eager to help or just have a little chat, making us feel welcomed.
The room and the shared areas were great and the backyard was a pleasant addition.
The location is as good as it gets, this part of Kadikoy is wonderful for tourists and such, you'll probably find everything just by walking around the block. And it's also close both to the ferry pier and metro/marmaray.