Is a 90% down jacket warmer than a synthetic one?

Yes, for the same weight. Down traps more heat per gram than polyester fill, so a 90% down jacket is warmer and packs smaller. The trade-off is that down clumps when soaked, while synthetic fill keeps some warmth wet.

Can I wear it skiing?

It works as a warm mid-layer under a shell on cold days, or on its own in dry, cold weather. It is not a waterproof outer layer, so wet snow and rain will soak the shell.

How should I wash a down jacket?

Use a down-specific detergent, wash on a gentle cycle, and tumble dry low with dryer balls to break up clumps. Never use fabric softener, and allow plenty of drying time.

The jacket is described as a down jacket with no hood mentioned. Plan on a hat or a hooded shell over it in wind and snow.

Is Colmar a good outerwear brand?

Colmar is an Italian brand with a long ski-racing history, so its outerwear is built for cold mountain conditions. Its down jackets are a step above fashion puffers in construction.