Wow, what a house! It is in a great location, with quick and easy access to the City Bowl, Camps Bay, Table Mountain, and other destinations. Josefine and Mattias are great hosts, very responsive, and accommodating. They also offered up some great advice on activities and destinations for our group.
As others have said, the house itself is a destination. It is very tastefully decorated and has lots of great little nooks to settle in with friends for good conversation. The rooftop patio with views of the harbor and Table Mountain is a fantastic spot for sun downers. The bedrooms and studio are all very comfortable. The kitchen is well stocked for most cooking you'd want to do. The pool table and table hockey games offer quick, fun entertainment.
Two minor notes. First, while the staircases are visually stunning (from the dining area it looks like you're in an Escher drawing!), the lack of hand/guardrails would make them potentially hazardous for young kids. Second, most of the outlets have been outfitted with Type C sockets, not the Type M you usually find in South Africa. Make sure you bring the right adapter!
I can't recommend the house, or Josefine and Mattias, enough. We had a great time there, and would definitely return if the opportunity presents itself.