My wife and I loved the location of this spot; it was easy to access the entire city from here. It's a large space, and the bed is especially comfy. Charlotte was incredibly friendly and responsive- she was a pleasure to deal with.
Really the only downside was dealing with the smoke. It's a non-smoking building, but it seems that one of the neighbors smokes inside and the smell of smoke makes it way into the apartment. Unfortunetly it impacted our stay.
That was it, though- I'd still recommend staying here if you want to access the beautiful city of Vienna!