I've been shooting with the same pair of Peltor 3M's for over six years now. They work just like the day I bought them and the battery life is excellent. And the sound is very clear, better than the other products mentioned in the thread. I can shoulder a rifle just fine with them, but I do put a ear plug in my right ear in case they happen to "shift" while firing. I bought mine from LaRue Tactical and if I ever need another pair for whatever reason, I'll pick up another pair. I highly recommend them over the Impact models or the Pro Gold stuff.
Buy once, cry once, hear everything.