In reply to alimckay:
Thanks for the replies so far.
Re the Rab Neutrino 600 That claims to be 600grams of 800 fill rated to comfort -5 and comfort limit -12c @
Whereas the equivalent Lightline reg in this version has 580grams of 750+ fill Goose Down with a comfort rating of -1 to -5c
this is where I get thrown as that seems quite a big difference in ratings between the two for quite similar specs.
Think Ive convinced myself to go for the older version of the Lightline (although the new version is even nicer but at twice the price at over £450 for 650 grams of 850 Eu fill)
Numbers numbers numbers, getting obsessed by numbers and still probably wont get it right