Backpacks and ski bags together: the two things a racer needs to get a full kit from the car to the hill and from home to a race weekend.
In practice most athletes end up with both: a boot-and-helmet backpack for the daily carry, and a padded ski bag for travel. The backpack is the one used every day, so it is worth buying the better of the two.
Look for a helmet compartment that does not crush, a ventilated boot section, and a bag long enough inside for your longest pair of skis.