I recently brought my Alpha 100 out of retirement, and golly what a difference from the Gentex.
I wear plugs and my helmet constantly, and as Steve76 said, you really DO notice the difference between Visor up and down.
I have a slight dip due to firing rifles in the military without plugs or muffs, but I try the darndest I can to avoid it going any further!
I see some of our guys unplug the APU from the 206B and L without muffs, and wonder if they really know...