We stayed here and loved Vienna, very stylish, opera, architecture and sophisticated. This Hotel was, I'm sure, thee place to go in days gone past, so what is left today is lovely rooms, refurbished & of a good size. These sit over a once grand foyer that has had the misfortune of very modern lifts being installed and parts of the ground floor being sold off for high street shops. So dont go for the grand foyer & restaurant experience, but the rooms are great, simply because they are the original rooms with high ceilings and very good quality furnishings. Reception is very poor, cold & has only one member of staff on duty at any time, so again dont expect great service or a great attitude.
The location is truly central & once installed in this location, Vienna is on your doorstep, a must is the Opera & the Sisi Apartments ( Elizabeth Museum).
Just be careful should you order a cab from the Hotel reception- it will be a private cab & twice the price of a normal one!

Stayed at the Ambassador for a conference nearby. It is a great hotel. Lovely rooms with high ceilings and wooden floors. Very good breakfast and a popular bar in the hotel. It is within walking distance to everything. We also got a great price on the internet.

Lovely central hotel. We had a large room complete with chandelier and well appointed bathroom, although I could have done with more light over the mirror. We were a little disappointed to come back to our room after lunch and find the bed still unmade. We also felt that the staff could have been more friendly and helpful, specially in comparison with the superb Hotel Pest in Budapest. We paid our bill and hauled our luggage out with no offer of help, or even a friendly goodbye!

We spent two weeks in Europe, and this was one of four hotels that we stayed in. You can see our relative experiences in my other reviews for those respective properties. Our preference, in order:

#1 - Hotel Josef, Prague, Czech Republic
#2 - Hotel Sacher, Vienna, Austria
#3 - Ambassador Hotel, Vienna, Austria
#4 - Hotel Wolf-Dietrich, Salzburg, Austria

We stayed at the Ambassador for 5 nights, and picked it based on reviews here on TripAdvisor, cost and perceived value. Overall, it's a nice property and is legimately 4-stars, but it does shows sign of wear around the edges, like many reviews note. We stayed in the Beniamnio Gigli room (#124), which I think was a free upgrade, but they didn't tell us. We didn't book a theme room, but I think ours was a theme room.

Highlights: In-room Wi-Fi provided by T-Mobile (compatible with iPass, so was free to me). Two walk-out balconies overlooking the Kartner Strasse. Ideal location right on the Kartner Strasse. Beautiful decor with high ceilings, chandelier, detailed crown molding. Friendly and helpful English-speaking staff. Excellent concierge services (through the front desk) recommended good restaurants and booked all our activities. Free newspapers including USA Today and Wall Street Journal international editions.

Lowlights: Our TV went on the fritz and was never repaired, despite reporting it and requesting a fix. Bed was a little overly firm, "king" bed was really two twin mattresses on a king frame (common in Europe). Housekeeping does not make up rooms until mid/late afternoon (when we were jetlagged and needed a nap) and barges into the room without apology. Continental breakfast is very expensive at 25 € ($36). The only lobby is the area outside the Morwald restaurant, where they don't like you sitting during restaurant business hours. We were not allowed to have a bottle of Sprite out on the coffee table during happy hour. The lobby/restaurant is on the first floor (first level about the ground floor), so if you're staying on that floor you have to walk through it to reach the elevators. It's often smoky, and it's kind of weird walking through while people are eating dinner.

Things to note: Cafe Europa is right next door and has a cheaper and better breakfast buffet for 15 € ($22). The McDonald's right next to the hotel (on Johannesgasse, half a block off the Kartner Strasse) has a free Wi-Fi hotspot. Not sure if it belongs to McDonald's or is another business nearby, but it's free and available to use.