This is a great place to stay. It's not palatial but great value for the money. It has all the basic necessities you will need, perfect for the sole traveller, manageable for two. The location is convenient and safe for exploring the city, the centre being around 15-30mins walk, depending on where one is headed. Of course, this is Vienna so the tram system will get you anywhere quickly and cheaply. Surrounded by stunning architecture, all the major sites are easily accessible. Excellent coffee shop conveniently close. The apartment is on the ground floor but this isn't a problem because it's very secure and the advantage is that you don't have to trudge up flights if stairs every time you return from a day's sightseeing. Lots of little extra touches like a beer in the fridge for when you arrive and the kitchen (albeit tiny but, hey, you're going to eat out anyway) is well stocked with tea/coffee/condiments. There's even good quality toilet paper!
Most reassuring of all is Ray's rapid communication to any questions. If you're new to Airbnb, this is what you need.
Highly recommended.