I bought a pair to try out this past fall during deer season. I hunt with a .300WSM, aka big boomstick, so it was a pretty good test!
The good news: They work.
The bad news: They work so well that it makes hearing deer and other important woods noises very difficult.
My verdict was they'd be fine for shooting, but not for hunting. Back to the search for a cheap Walker's Game Ear setup for me...