I just ordered a Killer B Stinger. I find I am always uncovering an ear so I can hear around me. I hunt with my daughter a lot, in the woods with rattlesnakes, parks with people, ect. I am excited to try them out. I think the only issue I will have is at the beach. I will keep some foam earplugs to insert in the off ear just in case, but don't think it will be a problem. For my style of hunting, they just made sense.
I read good reviews on both the Stinger and the Rattler. I did not come across any other single earphone brands.