There are certainly great things about this place: the location and the terrace on the roof are standouts. The room was spacious and the bathroom was particularly nice. Ogul was easy to communicate with and always friendly in our interactions. If location and price are your main priorities I would recommend it.
Unfortunately next time I'm in Istanbul I will spend more money and stay somewhere nicer. This may have been good value for the price, but I found the bed much too uncomfortable (the springs squeaked loudly with every movement), and the room was musty whenever the windows were closed. The entrance door closing and people in the staircase were also quite loud at night (but the hosts provide ear-plugs).
The final thing is that they suggested that 90TL was the normal price to get to the airport with a taxi - it should be ~65 (since there was no traffic). The taxi they called for us turned off the meter and demanded 100TL at the airport. In the end it's only 30TL, but it left a bad taste in my mouth. They need to create relationships with honest cab drivers - I'm sure there are many in Istanbul.