When you are choosing a sleeping bag, one of the major things to consider is the insulation fill type. Sleeping bags are typically made with either synthetic fill or down fill. Each type has its own advantages and disadvantages, but a down filled is usually the best choice.
Down Sleeping Bags Weigh Less
The weight of your backpack and its contents is crucial when hiking the trails or even climbing a mountain. The more weight you carry, the sooner you will tire out and need a break. A down sleeping bag can make your pack a little lighter. Since a sleeping bag is one of the largest items you will carry while hiking, this is definitely a good place to save some weight.
Down Filled is Warmer than Synthetic Filled
Surprisingly, no synthetic fills can match down's weight to warmth ratio. Down traps more air and acts as a better insulator than any manmade fibers. When you are camping in cold weather, a warm sleeping bag is a must. You do not want to lose sleep shivering through the night, especially if you need energy for an early morning mountain ascent.
Down Bags Are More Compact
Pack space can be an importance factor when choosing camping gear. A down sleeping bag will compress more to take up less backpack space than a synthetic. That leaves you more room for things like food and extra clothes.
The Disadvantages of a Down Sleeping Bag
Although down sleeping bags have a lot of benefits, there are some drawbacks such as price and versatility.
In wet conditions down may be a poor choice. This is because a wet down bag becomes very compact, providing little insulation. This essentially leaves you with no sleeping bag for the night. To prevent this problem there are some made with water resistant or waterproof material. So you can still get a down bag for kayaking trips or rainy camping.
The only other real drawback is that down bags tend to be much more expensive than synthetic sleeping bags. You are usually paying for a higher quality bag when you choose down though.
Below price is a big concern, down insulation is usually the best choice for sleeping bags. When you choose down, your bag weighs less, you have more room in your pack and you are warmer.