When I stayed at the hotel I didn't get anything special as a Plat member except the usual access to the Executive Lounge, which was better than average. Platinum members could also take their breakfast from the buffet in the main restaurant as well (at least I was able to in 2007).
Overall the hotel is nice, with a great location. The only thing that turned me off were the really dark hallways.
We spent our anniversary there and will never forget it!
The hotel was one of the finest in Vienna, and the central location was supurb.
It was October and really warm, the airconditioning really paid off. We enjoyed a nice concierge in the morning and enjoyed the class of a very nice city. The front desk arranged a private tour of the city and it turned out to be delightful.
No worries with this place!