I had a very pleasant stay, and would recommend others to stay here, if your wish is to stay close to the action and central area of Istanbul. You feel comfortable in the room, so it is a good safebase after walking around the city all day.
You should note however, that if you are the "early to bed, early rise" kinda type, this place is not for you, as you can hear the music from the nearby nightclubs most of the night. You should also note, that the hotel has very thin walls, so you can hear EVERYTHING around you - that means the sounds of people walking up and down the stairs, talking loud, the person in the room above you walking around etc. If you are bothered by these things, don't stay here. The building is older, so this can't be helped.
Furthermore, the description of the hotel claimed to have a functioning kitchen, and this is not entirely true. You have the most basic of stuff, like a plate or two, a few utensils, one pot, one pan, one stove top (so you can only cook one thing at a time), a microwave, fridge, and a electric kettle, but you're still a long way to actually be able to cook something worthy of eating.
Besides this, you shouldn't worry about booking this hotel, not even if you're planning to stay for a longer period of time. It is a good place, and it has the best WiFi I have ever experienced in Turkey (big points for this one!). And the dürüm place next door makes the absolute best Adana dürüm, so buy this and enjoy in your room! :)