Synthetic insulation is your best bet if you ride in wet or coastal climates where snow tends to be heavy and damp. Unlike down, which clumps and loses its warming power when wet, synthetic fills like PrimaLoft and Thinsulate keep you warm even if moisture gets in. That reliability makes synthetic jackets a favorite for everyday resort riding.
The trade-off is that synthetic insulation is slightly heavier and bulkier than down for the same warmth level, so it won't pack down as small. But it's also more affordable, making it a practical choice for budget-conscious riders who still want solid warmth.
If you run into wet conditions often, tend to work up a sweat on the mountain, or just want dependable warmth without the premium price tag, synthetic is tough to beat.