Gyiseppe's place is very cute, and in an interesting part of Istanbul. The communication we received prior to arriving was excellent - with great instructions for arrival, and a good introduction from the landlord.
There were five of us in the flat - and that was really as many as could fit. I'd say there is a comfortable capacity for three or four people, but any more and it feels a bit crowded for a small place. The sheets and towels smelt a bit musty, and the flat smells a bit of smoke. We also had some problems with a shower not working, the heating not working, and the WiFi being inconsistent.
But overall this is good value for a base in central Istanbul. Great for budget travellers, but don't expect luxury!