We had a wonderful time in Istanbul! The apartment was 5-7 minutes walking distance from the "Blue Mosque" (centre of the Old historical town) and ca. 10 min from the tram (that gives you easy transport to the Metro and some ships too).
The room was nice and clean, with comfortable bed and the bathroom was clean too :)
There was a fridge, wi-fi, tv and even hot water kettle.
More importantly - the hosts were wonderful and there were absolutely no problems contacting them.
Another plus was the quiet neighbourhood (!).
I recommend the "Violin rooms" - great place, great location, easy transport. I'd rent it again if I come back. Salih offered even airport transfer, you don't want to take taxi in Istanbul:)