I just stayed here for five nights with my husband and two year-old daughter and parents in a separate room. Overall it was a great stay and I would definitely return.

Positives:
1)Upgrades! I had booked two rooms on points. One room was upgraded to a fabulous two room suite (with two small bathrooms); one room was upgraded to a larger regular room with a very large bathroom. Very, very nice.
2) Staff were very cordial and helpful.
3) Location is outstanding. You are at the epicenter of Vienna.
4) For plat breakfast, given full buffet in restaurant.

Negatives:
1) Construction is still going on. I never heard anything, but the main restaurant is still closed. All meals are served in the banquet hall in the basement.
2) The breakfast was fine but not particularly exceptional. I would not have wanted to pay for it.
3) The mattress was QUITE firm.

Again, overall a great stay and will definitely return.