I’ve used the MSA Sordin, originally purchased from Tactical Command Industries, since 2006. The original ear inserts tore and replaced with gel inserts. The battery terminals were replaced in 2007 and have been working since without issues.
Though the Sordin set is comfortable, I prefer the open air against my ears and transitioned to the Surefire EP4 Sonic Defenders. I don’t hear verbal communication as clearly, but I don’t talk much to anyone anyway. There is always the polite request for verbal projection.
The Sordins are my standby ear pros for new shooters — or if it’s cold outside (they double as ear muffs). However, I’ve been taking a liking to the Pro Tac Pro Ears I won at a Gun Blogger Rendezvous a few years ago. I initially dismissed them because they’re bulky, and quite expensive, but they are comfortable, made in the USA, and the sound system doesn’t cut out 100%. As opposed to cutting off sound, the Pro Ear Gold set compresses it.
Aside from losing the right ear plug of the EP4 on my first set, I did like them enough to buy a second set. If I were to purchase a Pro Ears set, I would consider the Pro Tac Slim Gold using Lithium 123 batteries.