THE best place to stay if you're in Vienna for a concert at Wiener Stadthalle; it's right across the street! Plenty of restaurants nearby with good food. I recommend Bierosophie. The accommodation was exactly what we expected. Secure access to the building and quiet at night. The host is great at communicating and the check-in process was very smooth.
My girlfriend and I don't mind walking and if you're the same, here's some info: Schönbrunn Zoo is 45 min walk, Haus des Meeres Aqua Terra Zoo is 30 min walk, and Museum quarter is also 30 min walk. A great microbrewery with good food is 1516 Brewery about 40 min walk. If you're not too keen on walking everywhere, fear not. There is a tram station 7 min walk away and plenty of bus stations nearby as well.
I definitely recommend staying here!