I have the Howard Leight Impact Pro Electronic Earmuffs and really like them for the price. The ear cups are quite a bit bigger than the Impact Sport, but they didn't seem to be in the way shooting my AR. They are a huge step up from the cheapo Caldwell electronic muffs I had.
I have 3M Peltor Ultimate 10 Hearing Protector I got from Amazon. NNR 30 db. A little bulky, but they are really comfortable, quiet, and I never have ringing in my ears, even after shooting next to a guy with a .50 cal Desert Eagle for a half hour. Can't beat $20, and you can always double up.