The Dillon muffs in question are recently introduced and appear to be competitive with the ProEars Slim LE's.
I have had experience with both the ProEars and Peltors and find them both to be excellent examples of fine hearing protection.
Personally, I am partial to the ProEars from personal experience. The Tactical series along with the Magnum for extra protection are must-haves for any serious range use.
Tim
http://www.streetpro.com
Street Smart Professional Equipment