I just completed a three-night stay here. It's been open since around 04/01, with the complete opening in early May (so I hear). I would give it a mixed review overall.
The best part of the hotel is the setting. It's in Besiktas one block off the Bosphorous down the hill from Macka, within striking distance of both Taksim and Ortakoy (probably half-way between the two). It's arguably the best place to be in Istanbul as a tourist (assuming that you don't want to be in the old city). The building and street that it's on are gorgeous -- they redeveloped two blocks of old row houses, which come together in a "V" where the hotel is. The buildings are painted sort of a brown with white trim, with striking white lighting on the outside. My room had a terrace, from which the views were also beautiful (of a street, mind you, not a skyline or the Bosphorous). The rest of the buildings are, or will soon be, upscale stores and services. The architecture is really something.
The lobby is typical W -- dark, with modern furnishings and pulsating music. It's pretty small as well. There's a small check-in area, then you go up a ramp through a curtain to a second lobby, which has another single desk (a conceirge perhaps) and the elevators. All of the floors and walls are black. The layout is strange, as I suppose the hotel is on a steep hill. There are sort of staggered half-floors, and some of the rooms are so split. There are four floors overall. There is no pool, but a "day spa" which I didn't visit.
My first room (more on that later), which was billed as an "upgrade," was long and narrow, with the typically modern, avant garde, furnishings. The room size was OK; maybe a bit bigger than the average room at the InterContinental, Hyatt, or Ritz-Carlton. The sheets were extremely comfortable and towels plush. The TV was strange -- it was in a wall unit that was basically a brick wall, with sculptures on the left and/or right sides of the mounted TV and the whole thing covered with smoke-colored glass., about nine inches away, parallel to the wall. This was a lens over the TV that made viewing less clear. And, since the TV was on the opposite side of the room from my bed, it presented a volume challenge for some channels. There was also a large work area with a table lamp, and only European style 220V power plugs. Channel selection was average, but they had pay-per-view movies, which is unusual for the city.
The lighting system consisted of buttons for "wake," "work," "sleep," "wonder" (red mood lighting), etc. The room also featured two VoIP phones, one cordless, with menu options for ordering room service, getting an internet (wireless, TYL 33 per day) password, and other features. The room had an iPOD docking station and Bose stereo unit with a CD with mood music.
The bathroom was also typical W -- very elegant and modern. The shower was a large room with two options, a hand-held wand or a rain-type showerhead on the ceiling, whose diameter was enough to entirely cover someone showering. It was very nice. There was also a cord, like one that you would use to close blinds, hanging from the ceiling of the shower. I pulled this as hard as I thought I should, but couldn't figure out its purpose. (One note: There is no door on the bathroom. The shower and toilet were in separate small rooms, but the sink area between them was just off of the bedroom.)
The hotel has an attractive, modern two-level restaurant and bar. I didn't patronize them, but they had a nice drink menu with typical silly Istanbul prices (YTL 29 for a cocktail). The menu was a type of Asian-fusion, that didn't look too interesting. Off of the lobby there is a room with low sofas and tables, which serves as a lounge I suppose.
The one major issue that I had was with the climate control system. When I entered the room, it was unbelievably hot (29C), with no way to control it! It had a typical on/off/auto menu and temperature control, but none of them worked. When I tried to turn it on, nothing happened. When it was off, it would go on periodically for no apparent reason. I opened the windows and accepted it the first night. The second day, various rounds of technicians couldn't fix it (despite several promises), so I moved to a different room at the offer of the manager. The second room was more or less the same as the first, except more square. In the second room, the temperature was reasonable, but they told me please not to touch the climate control unit. Not a great solution, either. Let's chalk this up to the newness of the facility.
I made a lot of service requests, and the staff was very responsive. In the course of my temperature travails, I spoke with someone from the "welcome office" and a manager, who were both articulate and helpful.
When I checked in, the first agent had difficulty. I had separate reservations for successive nights that I wanted to merge, but she didn't grasp this. It was apparent that she was reading from a script. Eventually someone else came over to help. Three separate officials greeted me, introduced themselves, and wished me a pleasant stay. I assume that this is because of the newness of the property. It's noteworthy that the service was quite opposite to the usual aloof, "I am too hip to actually help you" attitude of W's in the U.S. at which I have stayed. I asked if they had a shoe shine, and they said, no, but we will take care of it for you, which they did promptly (at a charge of YTL 10 -- not horrible, but most peer hotels in Istanbul have complimentary shoe shine). I also asked at various times for an iron and board, power plug converter, newspaper, cheese plate, and other amenities, which always came promptly. (I will be curious to see what's on my bill.) At one point I asked for a few bananas, and they came along with a strawberry smoothie, which the person who delivered it said were compliments of the house.
Housekeeping was fine, but a few minor gripes -- they didn't replace the lotion, nor the wine glasses (even though I had a half-drunk bottle of their wine corked on the tray). But overall I felt that they did a good job.
So, in sum, I would say that I received the typical W facilities (including some nifty features in the room), and better-than-expected service, but one major glitch that I hope will be resolved in the future. It's worth a try.