First of all the positives: amazing position, beautiful building, nice spaces and overall great value for the money.
Now the negatives: cleanliness left a lot to be desired (e.g. hairs in the sheets, dust on nightstands, corners etc.). The bigger room is very noisy, as the windows don't insulate at all from the street. Also, the whole apartment is very cheaply and sparsely furnished.
Two things stand out which could easily be addressed: no trashcan in the ensuite bathroom, and only 3 rolls of toilet paper for 4 people over 3 days (any extra you have to buy yourself!).
Would recommend it for the value represented but would not come back as there are way better apartments in Vienna in the same price range.