Stayed for three nights at the Hotel Hadrigan in October. The hotel is about 10 min walk (via the shortest way) to the Ottakring subway station which is another 10 min ride away from the city centre. However, as the walk to/fro subway from hotel can be quite deserted in the evening so it is best to walk on the major roads (instead of the shortest way) which takes an extra 10min.
All the staff we encountered were rather sullen and curt, though they would still respond to requests for assistance, albeit not with a friendly face. When we asked about the bus services available at the bus stop outside the hotel, we were told very curtly that we don't need buses because the metro is just 10 min walk away. However, we won't put it past them as they probably work long shifts and can be a little moody at times.
The room is as basic as you can get and the TV is rather dispensable given its small size and few channels. The heater would only turn on late at night so don't bother about the dials. The Wifi connection is either free or non-existent depending on which floor your room is on. We are on second level so we were able to get a decent connection (ask for the username and password from the reception), but there is no guarantee of internet access for those on higher floors as told by the staff.
The breakfast buffet is rather cheap at at EUR 5 per person, and provides some choices of cheese, ham, bread and juices. Quite good for a rather satisfying breakfast.
Not exactly the best place to stay in Vienna given there are other choices at slightly higher prices and nearer to city centre. But if cost is your top priority and you do not mind hostel-like basic room and service as well as the less-than-ideal location, then Hotel Hadrigan may fit your bill.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC