In reply to RoK:
Good question Ronan. I've had my DAS so long I can't really remember what it was like when young, but I don't think it has degraded particularly significantly. I don't know what insulation is in there though, it might be a pre-Primaloft one.
I definitely remember seeing friends synth sleeping bags in the 90s noticeably collapse over a number of years, but perhaps modern synthetics are better?
With the Fjörm specifically the synthetic bits are rather small so I can't imagine it being a big issue, of course though I have only had it 6 months or so, so you wouldn't expect any thing noticeable in this time.
It is a good point though as there seem to be more and more mix synthetic and down jackets around, but one plus point for all down jackets has always been how well they last. My TNF Nuptse, bought in Dec 1995 still works fine and will be 20 soon-ish!