In reply to Steve Humm 4395:
from recall - and noting how shit the buffalo website is in telling you differences between the differing garments - the S6 has a heavier and therefore more wind/showerproof pertex, and is about 2 inches longer at the hem.
i would say that the S6 is more geared towards marginally less strenuous winter walking, and the MS geared more towards the mountaineering/climbing/active end of the spectrum. i rather doubt that you'd notice much difference between the two in terms of performance on any given day, but i imagine that the S6 is warmer and more weatherproof in absolute terms.
broadly, i'd have said that the saving incured by buying the MS rather than the S6 would pay for the hood or a pair of mitts and would therefore be the better buy.
on a somewhat windswept hilltop radar station in the Falklands, the S6 and MS - along with the Montane Extreme and the Snugpak shirts - are pretty much compulsory. the choice seems to be purely personal with no real swingers either way - though the Montane became very fashionable, but its shit pockets, chest venting and velcro-tastic map pocket have led to a big dip in its popularity.
