My three friends and I had a great time in Vienna in the appartment. The location is great, if you don't mind walking you can walk to the city centre.
The house is well equipped and you can comfortably cook in the kitchen.
The couch is comfortable but the house has only one bed so four fit good but it may be too packed for a long time (we have just stayed three nights, but I think that a longer period of time the house could be small for four).
The only think we didn't like was that we had to pay 20€ to the person who came to open the door for us and I think that that should be included in the price payed in Airbnb.