Very nice appartment in a convenient situation. We felt as if we were at home. It may be simple but it's got the things you need. It's closed to the subway (to stops until the main station in city center), closed to a supermarket and closed to some restaurants and bars.
When we had a problem Gudrum came to fit it, and she gave us some advices when we arrived.
In the other hand, it was very hot and it didn't hace any air conditioner, but I suppose that's normal in Wien...
In short, I would recommend it!