The apartment is facing a square and so light is coming in, even though it is oriented north, without direct sun. Besides there are high ceilings and that is really pleasant. The apartment is as described, no bad surprise. It is rather well equiped but note that there no extra knives and forks which can be limiting if you have your meals there.
It is less than 10 minutes to the metro so you can be anywhere in the center of Vienna in less than 20 minutes.
I had no direct contact with Nadina, I think it is a renting company (many other apartments with a key box in the building). Nevertheless communication was smooth, I had all the necessary information and there was some flexibility on the timing, so nothing to complain about.