The most important thing is that you get something that fits your head snugly, offers sufficient protection and that you're comfortable. Beyond that it's simply about choosing lens type (clear, yellow, or smoked).
Yellow lenses amplify ambient light, making it easier to see, however as it tints everything, colours can be harder to make out. Clear lenses offer a simple shield/barrier, and translate the image exactly as you'd normally see it. Smoked lenses offer protection from the sun, however as they limit the amount of light getting through, they are more difficult to see in low-light conditions
These Polycarbonate glasses are superb - lightweight frame, reinforced lenses for superior protection, optional elasticated strap to keep the glasses tight to your head, and lots of airflow to keep them from fogging.