I've owned both - Buffalo first, made to measure, then the Extreme. Hood on Extreme is much much better - the Buffalo one has flaps which can blow into your eyes, and kind of gives you tunnel vision - on the edge of dangerous in winter, and painful in the wind. The ventilation arrangements of the Extreme are also much better imo - you can use the diagonal chest zips to get very controlled ventilation, whereas the side zips (on both) are useful but in practice mostly covered by your rucsac belt. The hand warmer pockets on the Buffalo are not very sensibly placed - if you wear a rucsac they are under the belt, and the pockets also mean there is two layers of pile under the belt and over your belly - not very sensible. The Extreme used to have even more advantages - thin fabric under the armpits and at the cuffs for example, but these have been dropped alas.
Edited: 21/03/2011 at 19:04