I always played with either a full cage or a full shield depending on the occasion, since at some places the full cage kept fogging up so it was better to use the cage at those occasions.
I know that many players don't like how even a small shield, in their opinion, restricts their vision - especially the peripheral vision, and that is why they decide to ditch it as soon as they are allowed to. But I always felt comfortable with full cages and shields, and if I had continued to play I would've probably gone for the medium length shield myself.
The one thing that really sucks about full cages and shields is that they're a b*tch when you get into a fight with someone... you really don't want to be dropping your gloves in those situations.
Oh, and even though I always wore either a full cage or a shield, I still wore my mouth guard, because I always found that it helped align the jawbone better and in that regard it helped with the breathing... our team had them specifically molded for each individual which was really nice and really seemed to make a difference.
