Down or synthetic for 3-season camping?

Down (like the Kelty Cosmic 20) packs smaller, weighs less, and is favored for backpacking, but loses insulating power when wet and costs more. Synthetic fills (Teton Celsius, and the budget bags) are heavier and bulkier but stay warmer when damp and cost far less, making them popular for car camping and beginners. The verified-purchase ratings across both types are similar, so the choice comes down to weight, budget, and how wet your conditions are.