The apartment was in an ideal location for our needs as we were visiting Vienna's Christmas markets for our wedding anniversary. It was very clean. Although it is advertised for 4 guests, we found it very small for the 2 of us with our 4-month old baby. There wasn't really room for our bags, although it is worth noting that we had a baby travel cot set up in the bedroom.
Our main concern was the fact that the amenities are not accurate in that this apartment is advertised as having a lift, suggesting that it is accessible, however whilst there is a lift in the building, it has no relevance to the apartment - firstly because to access it you have to climb a flight of stairs and secondly because the apartment is on the basement level, down a flight of stairs where there is no lift access. This was especially inconvenient for us as it was our first time travelling with our baby and the stroller, so I specifically chose an apartment that listed a lift.
There is little to no natural light in the apartment, which wasn't a huge issue for us as we were out quite a lot, but was noticeable and is worth noting in case it's important to you.