Affordable, no-frills, basic but very clean. Staff were friendly and offered good advice on where to eat locally.
My only improvement I could think of is there's a larger than expected gap at the bottom of the room door which lets a lot of sound in from the hallway corridor. While the hotel isn't responsible for noisy tourists, a little soundproofing goes a long way.
The bathroom was simple, clean, the water was hot and the pressure was good - exactly what you want !
Simple things like a kettle and some tea/coffee making in the room would be a bonus else the room felt a bit spartan.
If I came back to Vienna and the price was right I'd likely stay here again, I didn't need an expensive hotel with a restaurant, bar and all those amenities. It's an ideal base to come home to and sleep because great breakfasts are just around the corner.
It's a 30 second walk from Wien Mitte station and is nicely enclosed, private and quiet.