The location is the best (about 3min walk from HBF : central station)
from HBF you can reach pretty much every tourist spot in 15-30 mins, so i would recommend to stay near HBF. not bad price since Wien is bit expensive city.
the room is quite small, but affordable for 2 people, recommend to have breakfast (9 euro /person) which has fresh breads, jams, cheese and stuffs.