Berk's place was fantastic. It was perfectly located about a 5 minute walk from Istiklal. The watch is quite steep, so if you have mobility issues, it may be something to think about it. We were close enough to the action, but far enough out of the way that we didn't hear any noise. There was someone waiting for us to check in upon arrival, and he took us through all the amenities. There was a folder on the coffee table that gave us facts about Istanbul, recommendations on places to visit and a few business cards that had the address and map of the surrounding streets. This was incredibly helpful!
Berk was also kind enough to leave us some drinks in the fridge, some candy and a bottle of wine.
The apartment itself was gorgeous. A huge back terrace space to sit out and talk, modern amenities and it was sparkling clean.
I wouldn't hesitate to recommend Berk's place to anyone considering a stay in Istanbul!