good resources on this site, lots of knowledge from the field.
I have the leupold alumina cover on the eye piece of my luepold 2x scope on my FA 83. I also have a butler creek on the same scope which is mounted on a Ruger Blackhawk Hunter.
The luepold is expensive, but I definitely prefer it to the butler creek cover. it flips up easily with a convenient thumb latch, and flips up quieter that the BC cover. it also stays closed unless you flip the switch. in addition, it looks sleek, and not as clunky as the slip on covers as it screws into the pre existing threads on your scope.
I hunt in the Pacific NW rain forest now, and it has been a must have. I field carry in a holster, so As 98Redline stated, I don't worry about the objective lens as it is covered by my holster.
I just dry fire practice with it on, and it has become second nature to "flip the lid" while in the motion of lining up for the shot.
"If you are going to go through all the trouble to put a hole in something, why not make it a big one?"