This is always my go-to place for lunch downtown. Aside from the great food the owner is also hilarious. He often trolls his customers and regulars often play along with it much to the confusion of other new-comers. I've seen some people get actually offended over this, but I've seen many more come back to Istanbul again and again.
The bulgar wheat is great, as is the hummus, gyro plates, and hot sauce. Prices are good and they give you a ton of food. I honestly don't think I've had anything here that I haven't liked. It should also be noted that this a cash-only establishment and it is take out only (save for some stand up places to eat).
Overall, you aren't going to find better Turkish food in the city and quite honestly I don't think you'll find a better lunch at this price downtown either.