Located near to the train station (train takes 10 minutes to the first Vienna Metro station). Rooms are clean and comfortable, furniture is new, breakfast is abundant, offering also traditional austrian specialities.
Only a less positive note: we tried to have dinner on Sunday evening (around 20:30 !!) and the staff told us that we cannot, they were overloaded due to a big group. After insistence, we succeeded to eat an hamburger (good), a typical austrian soup (good) and a dish of spaghetti (note: if you are from Italy, never order them !).
In general: very good Hotel, in case we visit Vienna again, we will stay there !