Cons:
The apartment cleanliness was totally good, but the bedding set was awful. Pillows were full of short hair which is so disgusting. One more thing is that although our check out time was 11:00 am, at 10:00 am one lady started to clean at the neighbour room. (Talking loudly) We didn't know really why she was doing it. If you want to stay one night it is not a good option because of check-in and out time, specifically, you arrive in the morning to Wien. Till 3 pm you need to carry your stuff. Dan suggested putting them somewhere else for 5-10 euros.
This kind of information should be published publicly not after reservation. Dan is not really open for early check-in or late check-out a few hours.
Pros:
Check-in and check-out were really easy. Dan gave brief instructions to follow. The location was perfect. A few minutes walk from Stephen's cathedral.