For most resort skiers, a balaclava with 'Good' breathability hits the sweet spot. It handles moisture well enough for typical ski days—cruising groomers, taking laps with friends, and stopping for the occasional break. You might notice some goggle fogging when you're standing still for a while or really pushing hard, but it usually clears up quickly once you get moving again.
The advantage of 'Good' over 'Excellent' is balance. Balaclavas with excellent breathability often use thinner fabrics or mesh zones that let more cold air in, which can leave you chilly on windy lift rides. 'Good' breathability still traps enough warmth for comfortable resort skiing while keeping moisture buildup manageable.
Save the 'Excellent' rating for high-exertion days like touring or warm spring skiing. If you're a typical resort rider who skis at a moderate pace, 'Good' is all you really need.