Polyester Fill - Polyester insulation may not be as warm or light as down, but it's far easier to clean and performs better in wet conditions. If cost is a concern or you live in a wet climate then polyester insulation might be your best option.
Synthetic insulation is measured in grams, so a jacket with a 80g rating simply means that a 1 meter by 1 meter piece of that particular jacket's insulation weighs 80 grams. The higher the rating, the warmer the outerwear.
DWR Coating - A Durable Water Resistant finish applied to the exterior of the garment.