I travelled alone and stayed 7 days at Guliz place. I really enjoyed it. You can expect a cosy and clean room with everything you need. The flat is very close (10 min walk) to Taksim square, where you'll find shuttle buses from and to the airport. There are plenty of nice restaurants and bars in the neighbourhood and you can easily explore the neighbourhoods Galata and Karaköy. I did everything by walking, except of my visits to Kadaköy, Moda and Üsküdar, which needed a ferry. Guliz is really helpful for any travel information and quick in responding. This stay felt to me as living in a shared house again, with an easy going roommate. :-)