The location is so convenient to ferry, bus and tram to anywhere you want to go, five minute stroll to each. But the hotel is set back from the street so you don't get the noise. Best of both worlds there! Or just walk around this gorgeous place to find yourself in a tranquil forest, an open-air museum, a prince's estate, a fun park, a cafe or restaurant... you really have everything on the island to enjoy your stay without leaving.
The grounds of the hotel are beautiful and peaceful. There's a large sauna too.
The breakfast is fantastic. A great range of food and large, well-spaced tables so you don't feel crowded. The only tiny thing I would change: provide cow's milk among the range of other milks (e.g oat, lactose-free).
Overall, I won't even bother looking for another hotel next time I'm in Stockholm. This is the place to be.