This hotel stands out on a limb away from any main centre so its not ideal if you do not have transport of your own. When you arrive you pass through a security barrier and parking underground is chargeable at 18TL per night which is not great when you consider that you are already paying to stay at the hotel.
Disappointing for a Marriott Hotel there are plenty of other alternatives in Istanbul where the bar charges are more reasonable and with better rooms. We paid 50 TL for a toasted sandwich and two beers which by Turkish standards is daylight robbery.
Check in was fairly straight forward and efficient and the staff were pleasant and helpful. The room was large but airless and with no way of opening up the windows it felt oppressive and very much a utility rather than a pleasant place to stay. Avoid the mini bar or you will be charged a small fortune as seems to be the case with the breakfast.
On the upside the rooms were clean and with all the usual facilities you would expect from a Marriott hotel. Would I book this one again? Probably not.