I have to go with open face too. Prefer to see where I'm going. I have a Caberg open face but the visor covers your full face so no bugs. I have a full face too, that I used to wear for long runs as I find open faces are not much good at high speeds. Ended up with the visor flattening your nose.
or the wind gets underneath and the lid tries to act as a parachute.
But my new bike has a full screen, first bike I've had with a screen and the reduction in wind at high speeds means this no longer happens
As for bugs and full faces. If you have the visor open you are creating a wind tunnel effect that sucks them right in there.