Ideal for a small family - four ideal, five max. Beautifully warm. There's only one toilet - be aware. Kitchen is one person at a time, so it's small but well-designed. Bedrooms and bathrooms are lovely - comfy beds and modern bathroom. Sitting-room is perfectly adequate. Dining table is a bit rickety, lots of spillages as children come and go from table. Stairs down to ski room are extremely narrow and steep - do not be fat or old.
Outside, the location is breathtaking. Picture-postcard Swiss Alpine valley, looking north. Watching the sun rise and touch Saentis (the mountain opposite) early in the morning is awesome - as well as watching the late afternoon shadows creep back up the mountainside in late afternoon. In plenteous snow, you are right on a splendid (mountain) road-based toboggan run which is shared with a blue ski run down to the valley - so that in good conditions you would not actually have to drive anywhere. And the nearest lift is only 300m up the road (an easy walk, not at all steep, even in ski boots). But do bear in mind that you are already at nearly 1500m on the side of the valley - and it takes 15 minutes to drive up/down from Wildhaus or Unterwasser even in good weather. So a few cm snow on the ground down in Wildhaus can be very different up here - the house has plenty of snow-brooms and shovels, for a good reason! Strongly advise adequate winter preparation such as 4x4 vehicle, winter tyres and screenwash mixture down to -25 (near-neat). In fact, if you're not 4x4, a set of snowchains would possibly be required. Parking a bit tricky - narrow road.
In summer, I can imagine the place would be idyllic. You're already halfway up the mountain, for high-level walking. A plethora of marked paths.
There are three medium-sized supermarkets nearby - two in Wildhaus and one in Unterwasser. Skating rink in Wildhaus. Two petrol stations. Two cash machines. Very friendly and expert ski hire from Karl Alpiger Sport. Nearest Cinema is down in Buchs. Best swimming-pool and leisure complex by far is the Saentis-Zentrum, just on the western outskirts of St. Gallen - about 50 mins drive, but well worth it - it is truly amazing (Sfr 140 for family day ticket including two sports and all pools, slides, baths etc,).
Altogether, highly recommended: very few nationalities here other than Swiss/Austrian/Liechtenstein/German. Pretty undiscovered by the braying English halftermers. Hans-Peter has made a super house, and is a very welcoming host.