I went to Istanbul with my boyfriend for our summer holiday. We stayed at Ergun's apartment : very well situated in the heart of Taksim, a very animated neighbourhood.
The apartment had all the basics that an apartment should have: laundry machine, iron, vacuum cleaner, and the most important thing if you're going to Istanbul in the summer : A/C!
In the night it gets quite loud because it's surrounded by bars and restaurants. But that's normal since you're in Taksim.
We had a really pleasant trip in Istanbul and Ergun's place was perfect for us !
I highly recommend his place if you don't have any problem with the 5 floors that you will have to climb everyday :)