I get the feeling that the other reviewers are hotel employees because what they write is simply not true.
This is a 4star hotel but in reality its a piece of junk. Its located in Kadiköy (asia side). If u have nothing important to do on the asia side then u have no business here :). Simply forget it.
However if u need to come to Kadiköy then i would try the Double Tree in the center of Marriott which is further out. This hotel has a good location and free internet. Thats about all on the upside.
The breakfast is the worst i have seen lately.