The best thing about Marmara Sisli is the location, Sisli is a nice neighbourhood in Istanbul, the hotel is 5 min walk from Istanbul most luxurious mall "Istanbul Cevahir" and the underground "Metro" station.
I was shocked when I saw the room, it's designed as a sleeping train room, very narrow bed, no bathroom, the toilet, sink and shower are just scattered around the room with no closed doors.
There was absolutely no space to put my luggage, not even a chair to sit on.
One good thing to mention was the Air conditioning was working perfectly in July hottest days. ACs are a major problem in most of Istanbul 3 and 4 stars hotels and is something you really need to watch out for if you travel during summer.
The cleaning was average, the bed sheets weren't changed daily but still my main concern is the size of the room and the fact that no closed bathroom exists.
Stay at Marmara Sisli only if you are travelling alone or with friends and only if you get a good rate and plan to go back to the hotel only to sleep.More