The apt is amazing, it has a big bedroom, a big livingroom a great kitchen, and well located. You can either walk or take the tram next to the building to all vienna's sights.
I had a great experience thanks to Stefan, that send us the best sightseeings, and left in the apt brochures to restaurants, pubs, a map and Vienna's atractions.
The check-in and check-out were in the exact time that we talked, having no trouble at all.