No suite upgrade as a diamond .... even if suite were available (- They just upgrade to executive room (as they do for gold). I would say treatment for gold and diamond is the same there.

Agree hotel is nice, rooms are great with stunning view (including the fact that they have smoking rooms) but room service is so so (forget the burger, it's not good at all).

Ex lounge is great and hotel is in very good condition. Location and area is a little bit a mess... you have to take a taxi because there is nothing around except buildings in construction.

If you can get a good price it's a serious option in Istanbul.