In reply to Kaito: scottish winter/summer alpine the rab would be OK for that, some himalayan stuff? again if trekking this would be Ok, but if you are thinking Mera or something then you want more than this,
If you are carrying stuff then try to get the best down bag you can afford as better quality downs means less of it, less weight,
I would generally say you can trust ratings on reputable down bag brands, cheap synthetic is always questionable
Get a liner and use the bag as a quilt down in the valley, this is assuming you are not using huts, and are bivvying/tenting in the alps up high.