We enjoyed our stay here - Sascha & Marina where very quick to respond to any questions that we had.
I would point out that this apartment would not work very well for 4 adults. There are only 2 beds in the apartment (one in the loft which is very large and good for sharing, and a pullout in the loungeroom) The the pullout couch was the most uncomfortable bed I have ever slept on and shudder to think about trying to share it with another adult.