overall impression I rate as...

Liked: location
Disliked: dirt

Comfortable

Liked: Really good hotel with a luxurious feel. Got an upgrade to a room with minibar, room was spotless and comfortable, with thoughtful touches (hand cream and chocolates by the bed, turndown service with classical music). The breakfast buffet is extremely good, they even had congee and herring salads.
Disliked: Would be nice if rental bikes were more lowkey available (more flexible hours, cheaper or pay by hours). The whole building (but especially hallways and to a lesser extent rooms) is quite warm. If they aim for sustainability perhaps they could not replace the towels if hung up. Only thing missing at breakfast was crackers.

Superb

Superb

Superb

Liked: In general everything was extremely good

Very good

Very good

Exceptional

Wonderful stay in Vienna

Liked: Staying at Am Konzerthaus was a truly enjoyable experience from start to finish. The entire staff was exceptionally attentive, taking care of every detail both in the rooms and throughout the common areas. A special thanks to Deborah at the reservations office, who went above and beyond to resolve an issue with our booking, her professionalism and support made a real difference. The breakfast was outstanding, offering a wide variety of high-quality options. We’ll definitely be returning for our next visit to Vienna.