For me, I have Sordins because I like taking classes. Classes are always outdoors, always with pistols, and never around dumb loud guns, for me. At a class, where I'm going to be wearing the ear pro for ten to twelve hours, and I really don't want to be That Guy that forces the instructor to stop before a demo while you put your ears on, the crazy comfortable Sordins are worth the premium. I can hear the instructor more clearly and am less distracted by side chatter than with Peltors or pro ears. I've never felt the need to plug under them.
At the range, I prefer to wear the highest rated passives I could find (http://www.midwayusa.com/product/783...uffs-nrr-30-db). I only wear them for a couple hours and I don't have to use plugs with them. It would seem like a real waste to me to use my Sordins inside.