Best car in the world when all a person finds as a fault is the sun visor. I love my Prius, although I notice the carpets are not self cleaning, what a disapointment!! Sorry, I know I shouldn't take the piss but I can't help it.
I drive a Scion XB and have the same problem with the sun visors as I am 5'7" tall I spend a lot of time with my hand in the air blocking the sun from my eyes. I found a upholstered sun visor extension called VisorXtension. I love it. Go to youtube and type in VisorXtension and give it a look. Adds another 4 inches to the bottom of my sun visor and extends latteraly as well. Let me know what you think the Scatman