All nylon construction including a hydrophobic swami belt, many padded harnesses trap moisture which freezes and can be uncomfortable.
Drop-able leg loops so you can enter and exit the harness while wearing crampons.
Highly adjustable leg loops that allow you to add and subtract insulation while being tied in.
Comfort is important because as you begin to tackle harder routes you will be hanging in your harness longer and longer. Do not worry about padding your clothes take care of that. But the harness has to