It's a superb location, it's a beautiful house and both deserve the five star rating. The windows overlook the lake, however they are tiny and guests are advised not to open them because of mosquitoes. The welcoming was a bit strange, as when going to the rooms the corridor was still full with plates form breakfast (at 5pm). The rooms are clean, welcoming chocolates are superb (the grand restaurant was to our misfortune closed that night) and we slept well.
Overall it's a good hotel, but the five star rating is overdone. It's something between a five star hotel and a good bed and breakfast. The location is good for sleeping and certainly for dining in the fabulous two star Michelin restaurant. If you have to do in Geneva there are hotels which are more centrally located.