I had to stay 3 nights at the Holiday Inn hotel on a business trip. The weather conditions were bad so our Turkish partners could not make it for some of the meetings and I had to go back a day earlier. The guy at the reception desk was nice enough to reimburse the already paid money for one more night even though I checked out at 13.30 which should be considered as late check out. So much thanks for that.
Breakfast was great, many things for every taste. The only thing about breakfast was 2 of the waiters who were terribly smelling of sweat!!!
My room was "exclusive" - pretty nice. My colleagues were in Standard room - just ok.
What I did not like was the lack of bathroom amenities, especially they did not have slippers in the room, which is an absurdity for a 5 star hotel.
SPA center was ok, the guy that was servicing the SPA was just on time when you need him, very polite, not so much pushing you to use the paid serices. We used only the jakuzzi, pool and turkish bath - those were free.

Wifi is available in the lobby only very frustrating, location very poor, elevators too slow, no proper heating in the lobby

At the end of our work engagement in Istanbul we booked this hotel for a Sunday night for a Monday departure as we wanted to avoid the horrific traffic jams of Monday mornings from the Asian side. It is billed as an "airport hotel" but it is actually a 20-minute ride away from the airport.
The hotel sits in the middle of highway exchanges in an industrial section west of "downtown." We were impressed with the lobby upon entrance as the venue is relatively new and tastefully designed. The front desk person was a young man who checked us in with, what my wife calls, a haughty attitude. It was like he/they were doing us a favor for letting us stay there. There was no explanation of the hotel's facilities and services. He also tried to push a "promotion" of breakfast at 20 Euros each. We promptly declined this ripoff offer and were helped to our room by a friendly bellhop. As we were walking to our standard king room on the fifth floor we were struck by the lighting in the hallways. The owner(s) must have paid a lot of money for the design and construction of the dimly-lit hallways that looked like a night club setting.
Our room was larger than a typical Holiday Inn with the bathroom immediately to the left of the front door. The bathroom is fine but the shower head is situated behind a glass pane that only covers half of the tub (I ended up soaking the foot towel the next morning). AND the step up and in to the tub is very high. The towels are OK but there are no bathrobes or slippers. Deduct half a star from the claimed 5-star standing.
Next to the bathroom is a galley closet with theft-proof hangers (another question mark re. 5-stars) and the minibar. A tray with a water kettle and instant coffee/sugar/cream/tubes sits on a shelf above the minibar. (What?? No coffee maker with decent coffee?? Deduct another half star)
The bedroom is nice size with a soft king bed and several pillows two of which are marked as "firm." Nice!! There is also a work desk/shelf across the bed with a small flat-panel TV set and a work chair. To the left of the bed is a nice leather chair with a matching ottoman. Nice!!
When we looked for printed materials re. WIFI and could not find any we called the front desk. We were informed that there was no WIFI but we could use the internet via cable. When I asked why there is no WIFI--even at a fee-- in guest rooms the same haughty young man told me that only the Executive floors had WIFI as a sign of exclusivity. I also knew that there was free WIFI in the lobby, the restaurants and the garage. So much for "exclusivity." Anyway, we asked for an internet cable brought up by the same friendly bellhop. The next step is bizarre as to sign in I had to enter my passport number for "user name" and the room number for the password. Not nice!! After repeated efforts to sign in we gave up and called for the technician to come in and help, which he cheerfully did. AND there is a cardboard sign that says that the hotel monitors internet usage and will block "undesirable" sites. What?? WHO are you to impose your moral values on your guests? NOT NICE!! (Deduct a star from the now-4 stars.)
This attitude is somewhat tempered by the wonderful attitudes of most of the staff including Ms. Arzu and Ms. Gulcan at the lobby bar (who cheerfully helped me open my bottle of wine with nary an attitude), the young waitress at the Sultanate Restaurant and the shoe-shine person in the lobby.
Oh yeah, we had dinner at the Sultanate which was tastefully designed in an Osmanli (Ottoman) style. (VERY NICE). We chose the open buffet which was rich in salads and starters but we had to order our main course with the waitress. Due to a mix up, I think mainly because of me, we were brought plates of half portions of a fish fillet and bonfile (tenderloin steak). The fish was very acceptable but the "tenderloin" was very tough and left uneaten after one bite. The waitress offered to replace it with some more fish but we declined as we had plenty of food. The best part of dinner was the dessert table full of familiar (baklava) and unfamiliar sweets and fruits to satisfy any sweet-tooth person. Excellent!! The total bill for two came in at 99 TL (Turkish lira) with no drinks.
The next morning checkout was hassle free and we were shuttled to the airport in the midi van that runs every hour (Not nice) and departs for the hotel from the International terminal only (not nice).
The Bottom Line: A very nice and new venue that suffers from owner/managerial attitudes as Fish Rots from the Head.
Is it truly a 5-star hotel? NOT by a long shot.
Is it a true 4-star hotel? Maybe, as it is a 5-star wannabe; but beware the breakfast scam, the WIFI strangeness and BIG BROTHER/SISTER watching your internet use.

Spent one night here whilst in transit and was pleased with this hotel. I had previously looked at other reviews about the hotel and wanting a quiet room, asked for a room on the 9th floor or above. The room was very good and there was no traffic noise at all.
Internet is free from the lobby, all one needs to log in is their passport number and room number.
International customers may prefer the buffet style evening meal, slightly more expensive but may be more suited to their taste.
The only thing which I hope the hotel will change is the lack of English channels on the TV. I would like to see MBC 2, MBA action and BBC world news please. Other hotels in other islamic countries have these channels free so perhaps this hotel could also do the same.