High speed cutting tools are powerful staples of fabrication and modding, and require equally effective safety equipment. Ceramic cutting wheels can shatter in an instant, and cutting metal or plastic throws out a spray of eyeball-injuring particles. Wearing safety glasses or a face shield is a must.
I view the face shield as a low-cost upgrade over safety glasses. When wearing a face shield you can position your face anywhere when working, even in the direct path of thrown sparks. Another benefit is that face shields are harder to lose; traditional safety glasses are relatively small and can be easily misplaced under papers or in a drawer. The face shield takes up a decent amount of space, and as a result you’ll rarely lose track of it in your shop. Face shields also excellent for whenever you’re working with things that shatter, spray, or splatter. If you do a lot of dumb and dangerous projects (like me), this versatility is a must-have.
In conclusion, protect your cheek meat. Eye protection is a must, and wearing a face shield allows you to get up-close and personal with your work.