This is a fabulous place to stay in Vienna!
It is in the perfect location- 5 min walk or less to Stephansplatz, half a block from Figlmueller (most famous Wiener schnitzel) across the street from a very good cafe (Cafe Diglas) and I could go on. Super easy for transport everywhere- you are at the heart of the city!
Staff is amazing!!!! Vera responded to questions extremely rapidly, very accommodating! (Even when she was off, Niklas responded to email almost immediately!). Asked for early check in and they made it work! We made it through the the airport in record time and arrived 30 min even earlier than predicted (after overnight flight from USA with kids). Two staff members called Vera immediately, she was there in less than 5 min and we were in the room immediately! They appear to be doing SOM renovations/apartment conversions but always blissfully quiet and most accommodating and incredibly nice staff ever!
As for the roo- we stayed in 301/311- two bedrooms, kitchen and living room with sofa bed. My family (2 adults, 3 kids) loved it. It is incredibly posh, a bit awkward layout given it is an older building updated to posh apartment and done extremely well. Beds are definitely firm, everything else fantastic!
I normally reserve my highest ratings for incredible resorts, but I cannot imagine a better place AND staff for a stay in Vienna! This is the best you will find- book here if available and consider yourself extremely lucky!