Güven Bey and his team at Saray Apartments is very helpful and prompt. Our flight arrived earlier than scheduled and so we reached earlier than expected, to the apartment. Although Güven Bey wasn't there himself, he quickly asked someone to come and help us check in (at 10pm). The apartment was pretty much what you see in the pictures. It wasn't the largest or the comfiest of places, but you get what you pay for. At the price point, the place is good for 5 people.
The place is 8-10mins by walk to the Blue Mosque and Aya Sofya, but its rather steep uphill, so beware of that in case you have a problem with climbs!
One thing the place lacks, if I be critical, is windows. There's hardly any sunlight entering and no view, which can make you feel in a cramped space, but, if you're planning to absorb Istanbul in its true color and use an apartment to sleep, in an amazing location, this is a very good place!