I suggest wearing a full mask (metal, plastic, whatever). If you baby the itech shields you can keep the clean and keep them from fogging (right now I'm running the itech deluxe II full mask). Cages are really easy to run, and cheap as well. That's a great first step if you don't want to deal with the hassle of running clear plastic.
Shots are incredibly fast. In less than the blink of an eye someone's deflection can be in your face. I can't recall how many follow-through's, high sticks, people's stick coming up high, etc that I have taken to the mask. And the puck as well, people trying to clear the zone, especially during power plays. Hell the other day I was skating by the goal after the other team scored on us. After the whistle, my defensemen decided to wind up into the boards. His windup went right into my face. I didn't see/expect it at all, and his stick's blade hit me hard square in the face. If I didn't have a full mask on, I would have been in the ER having reconstructive surgery.
Your choice. Me, I have always and will always skate with a full mask (cage and now plastic).