This is a great find! Cheap and suprisingly large, it's only 8 mins walk from a train station which is itself one stop from the Hauptbahnhof. So it takes a mere 15 - 20 mins to get straight to the centre of Vienna.
There are several supermarket type stores within 5 - 10 mins walk too.
Mary is an excellent host in regular whatsapp contact with you throughout your stay. But quite unobtrusive. You can come and go as you please and the self check in works perfectly.
This beats the pants off hotel rooms!!