Rab - Alpine 600

April through October is my 400-time. In the end it really depends on what your personal comfort limits are and at what temperatures you would switch to the winter bag. I imagine the Norwegian coast is a bit warmer during winter than the Swedish coast, due to being more maritime? Regarding Rab: I have used the Neutrino 400 now during six seasons (this is the seventh) and I am really happy. It probably has lost a bit of fluff but that is to be expected after that time. Washed it once because I didn't use a liner in the beginning, but otherwise used always a liner, always hung it out after a hike and stored it in the cotton bag. If you have the money, go for it! They seem to have added a Neutrino 500 to their range and that would be my choice today, between the 600 and the 400. Otherwise, they also have a 650-cuin product line (cheaper but heavier) which is probably just as good.