I had a lovely experience in Ergun's studio apartment. I stayed for a whole week, so I got to know it and the area quite well. I felt like I had my own little home in Istanbul and after a few days I basically stopped feeling like a tourist and like I actually lived there.
Location was great - bars, restaurant, shops, and transit were all very close. I really don't think I could have been in a more fun and centrally located apartment. Travel to and from the airport was also very close. Travel to and from the main tourist destinations (and some off the beaten path locations) was great. (Also great location for LGBT travelers.)
Place was clean and well kept. Although on the small side and quite minimal, I felt it was perfect for the price. As you may have read, it can indeed get loud, but you're really in the heart of everything. The apartment also had everything I needed - iron, washing machine, some kitchen stuff, a/c. It's definitely not the place for a quiet getaway to do some reading, but great for the budget and convenience factor if you're planning on going out and seeing the sites.
Host was oh so great. I hung out with him a few times at his shop down the street, chatting over some coffee and snacks. He's very friendly and accommodating, as well as helpful for some information on the city and how to get around.
Overall, I would recommend the place.