There are two places masks may caused irritation. The bridge of the nose and the skin directly under the nose. A little discomfort in the store will grow to a large pain after skin or scuba diving. Buy silicone, not rubber. The material will last almost indefinitely.
Rubber is rotted by oil.
The oil on a diver's face will cause the mask to be useless after a few seasons. Also, the silicone masks allow more light to penetrate leading to less tunnel vision. Silicone will absorb colors from objects touching it. For example, if you attach a rubber snorkel or snorkel keeper to the silicone strap of the mask, the black color will slowly be absorbed into the strap making it look permanently soiled. If mold begins to grow on any silicone material it will embed itself in the material.