know this:
down is: warmer than synthetic ounce for ounce, retains shape and loft better, lighter than synthetic, more compressible than synthetic, wicks body moisture and overall lasts longer than synthetics.
however, down is also: more expensive,looses its heating properties when wet and takes forever to dry, can contain allergens and must be dry cleaned.
when thinking of purchasing down, pay attention to the loft rating. the scale ranges from 400-750. anything 600 or above is considered high end or high loft goose down which is what you want. if there is no loft rating on the product it is prob because it is below 400.
that being said, i have a columbia high loft goose down jacket that i have not been able to wear anywhere because it is too damn hot. also, i have a cheap old navy down vest (without a loft rating on it) that is very comfortable in the winter.
the jacket you listed looks to be a hell of a deal to me. if i was in the market, i wouldn't hesitate. mountain hardwear makes damn durable stuff imho.
synthetic is water resistant but retains its heating properties when wet and dries quickly. today's synthetics are getting pretty damn close imho.
enjoy!