After checking the reviews of all hotels I booked the Kaiserin.
We were extremely happy with the hotel, especially after they happily moved us into a room away from the building site next door. The staff were indeed very friendly, the hotel suites large and clean and the breakfast is a lot better than elsewhere.
However.
We had a trip to the Tirol and upon returning for a couple of nights prior to our flights we were told that our room had been cancelled by phone. As the trip was a surprise destination honeymoon and no-one knew the destination except me this was impossible - who would cancel their own honeymoon?
They did organise an appartment next door but our trip was tainted and we didn't quite get the same friendly service as others - and certainly no waving us off.
In summary, a great hotel but triple check your reservations.

Have just spent 4 nights in the Kaiserin Elisabeth. What a wonderful hotel and situated right in the centre of all that is happening. From the moment we arrived to the moment we left the staff were so helpful and friendly. Our room was superb, ample room, spotlessly clean with a wonderfully comfortable bed. I couldn't believe how quiet it was at night considering that our room overlooked the street - it wasn't like staying centre of city at all. Breakfast was ample and we felt like royalty with the solid silver teapots and milk jugs!.

I cannot recommend the reception staff high enough - they were so helpful in organising concert tickets, offering advise etc and had a smile and a word every time we passed through. They even remembered our room number each time we checked back to the hotel. They organised taxi for us to the airport (€33) and stood at the door to wave us off. It was like visiting family!

Thank you to previous reviewers as otherwise I would have missed out on such a lovely experience. I cannot recommend this hotel enough and can't wait to return! It makes a change to all the multinational hotel chains where you are just a number in a room. If you are considering spending time in Vienna and this hotel is on your list of possibilities - you won't be disappointed if you book.....!

From the moment we arrived to the moment we left, the service, friendliness of staff, location, value for money was the best. We found this great little hotel after reading other comments in Trip Advisor - what a little gem in the heart of Vienna. Room was large, bed was very comfortable, the bathroom one of the best, breakfast included and the front desk staff the most friendly and helpful we have come across. We will return.
Madden's, Western Australia

The rave reviews are all true. Out of the three hotels we stayed at in Europe, Hotel Kaiserin Elisabeth was our favorite: the room was beautiful and big (we had the double superior, which is a suite); the beds, linens and bathroom were all impeccably clean and comfortable; and the location - if you've never been to Vienna before - was perfect. Breakfast was good and the staff at breakfast was always welcoming and warm. The front desk staff - I agree with one review - some were better than others.

Being a frequent business traveler, I've become quite picky about my hotels. This hotel I would recommend as a must stay & worth the extra euros.