The location is amazing for the Christmas markets at Rathausplatz, the museums and lots more Viennese gems. It's a large apartment with some beautiful rooms and good facilities.
For a very big group two toilets and bathrooms might be an issue but we were comfortable. The kitchen is small and limited if you wanted to make a lavish meal but there's so much great food in Vienna I don't think most people will need more than this.
Christoph couldn't be more helpful and it was all exactly as described: He arranged everything for our arrival perfectly. Better than a hotel in our opinion and you're right behind the Rathaus which is a real treat.