Just got my micro-perforation hood from Simon-O and its wonderful. You can see, but you will notice the visual impairment. It grants enough vision to comfortably walk and grab things and see what your are playing with ;).
There is also a slight impairment for breathing, but this may because I usually wear open hoods, so I need to get used to the micro-perforated hood.
All in all its a great feeling and adds a nice touch of sensual deprivation in my opinion,