Very nice and very clean hotel. Only 1 subway stop from the main Vienna train station and 2 subway stops from the main city square StephanPlatz.
The area around the hotel is super safe, relatively quiet, but there are several restaurants nearby, as well as a couple of supermarkets and drug stores.
On the whole, it is a very nice hotel where I would stay again without hesitation.
The minor negatives are that in the very rare and unlikely event of extreme heat in the summer, their air conditioner is limited to 22C. You cannot make it cooler.
Like many other hotels in Vienna, they used the old fashioned keys so you need to unlock your door when you come inside and then lock it again with this key from inside. No big, but would be easier if they had a card to open the entry door.
There are no USB ports, just regular outlets. Make sure you have the necessary adapters if coming from the US/Mexico/Canada/UK