If you want it quiet enough to fire a rifle indoors, try foam earplugs and muff-type hearing protection at the same time .
Muffs are easy to remove and reinstall between shooting sessions .
Sometimes my muffs rub against a rifle stock, so I may opt for foam plugs . The foam plugs I use are purple ones from the Phamacy Dept. at Walmart, which are available in bulk in a plastic jar . I think they are made by Flents .
If you are shooting near a rifle that can badly damage your ears, use foam because you won't remove the foam plugs absentmindedly and get hammered .
Carry foam plugs in your car for any emergency, such as shopping in a store that plays loud music or dropping in at a singles dance . They also make nice gifts for fellow shooters who forget their ear protection .
Hats and eyeglasses can interfere with muff hearing protectors ; one more point for foam .
The foam plugs get dirty and thrown out and must be installed deep and properly to work. I sometimes have to pry mine out with my car key or with the tweezers on my Victorinox Swiss Army Knife .
In summary : I haven't used electronic types due to cost . I do know that foam plugs belong in your shooting bag, glove box, first aid kit, survival kit, console, wife's car and maybe on your key ring . I have had muffs that wore out due to the foam inserts deteriorating but still like muffs and have a quiet pair from Cabela's .