Well, I was so satified with Ibrahim's flat that I can hardly find anything negative to say... skip to the end to find the "cons".
Ibrahim is very very nice and answered all our questions about Istanbul. He is so helpful that he gave us: 1) a travelcard to take public transport, 2) sanitized, supercomfy clogs for all of us, 3) TV controls switched to our native language! 4) a telephone to call him in case of need without having to incur in roaming charges.... What more can I say?? That I loved the flat and the area around. Yes, 4 floors without elevator are tiring, but the bright side is... a bright apartment! a lot of light and a nice view on the busy streets. So that the only evening I stayed at home because of the bad weather, I enjoyed myself with a delicious take out dinner in front of the huge TV set.

PRO:
- warmest host you can find
- trendy neighbourhood, much less touristic and much more authentic that the European side.
- cosy apartment: nice, simple and clean, there's everything you may need
- crossing the Bosforus by ferry gives you a completely different view of Istambul
- mattress was a godsend! best sleep ever had.

CONS:
- restaurant on the backyard can be a bit noisy, but double-glaze windows are very good at blocking noise
- no elevator and spiral stairway
- I think there's no aircon but I'm not sure, it was May and I needed no cooling at all
- bad smell in the bathroom due to badly designed sewage, but the bathroom itself is clean, just keep the door closed.