The apartment is gorgeous, to me it looked like something out of Architectural Digest.
It is well equipped with high tech appliances.
It is in a very convenient neighbourhood for visiting central Vienna,
and about 20 min. walk to the Nasch Markt (a large funky collection of food stalls, restaurants, flea market, etc.) and about 5 min more to Karls Platz (a gateway to central Vienna).
The closest U-Bahn stop is only a couple of blocks away.

There was a confusion about the initial key exchange (in good measure our fault) but Alexander when to great lengths to sort it out, including telephoning our home in Canada to try and get in touch with us.
My advice for travellers from other continents is to bring an unlocked cell phone and get a local SIM card as soon as possible.
Then you can coordinate with Alexander via text messages.

It was a lovely spot. We had a great time.