Okay thanks. I had heard/read that some people actually prefer the sight picture they get when leaving them on while shooting with open sights. And old Mauser k98's had a nice sight picture with a front hood:
http://ts4.mm.bing.net/th?id=H.4814435809165583&pid=1.7
...so I didn't know if there were any benefits other than protecting the front blade. But as I said above, it seems distracting with aperture sights, so I'll continue to leave it off.