In the field, I don't want anything over my ears; I figure there's enough space, trees, brush, etc. to absorb enuf sound to keep me from damaging my ears. (I could be proven wrong on this, but don't want to be).
At the range where I shoot, hearing protection is required. Everything's under a roof and the sound is intense!
I wear a set of the el-cheapo foam plugs that you scrunch before inserting, then a pair of muffs over the top. Between session when people are changing targets, etc. I slip the muffs off.
Those sound-reducing jobs sound pretty good. I just got some money for Father's Day plus my $10 gift certif. from Cabela's - think I might get me a pair o' those. (One more thing to change batteries in)