Yes, medium is the most popular ski goggle frame size because it fits the majority of adult faces comfortably. If you're an adult man or woman with an average-sized face, medium is likely your best bet. It delivers a solid field of view without feeling bulky or overwhelming your face.
The big advantage of medium frames is versatility. They pair well with most helmets on the market, and you'll find way more style and lens options in medium than any other size. The field of view is broad enough for all-mountain skiing and riding without the fit issues that can come with oversized frames.
That said, if you have a notably small or large face, medium might not be ideal. Goggles that are too big leave gaps that let in cold air and cause fogging, while goggles that are too small can pinch and restrict your peripheral vision. Always try them on with your helmet to confirm the seal and comfort before committing.