In a few words I highly recommend Halil's apartments! It was amazingly clean, from the moment we stepped in we felt like home. It was literally 5 minutes from the center of Taksim square. It was really cozy and warm all day even if we visited Istanbul in February and the weather was quite chilly. Warm water was available every time of the day and the WiFi had coverage in all the apartment.
Halil was a great host and he was there to suggest us both were to eat (2/2 places were amazing) and some activities we could do. All along had a great experience!