It really comes down to personal preferrence. My understanding was old/new style, not current model diffs. I've rowed with both, and I prefer the thinner blades over the thicker. A guide friend however prefers the thicker, his feeling is they don't jam into the rocks and get stuck as often. Either is a great deal better than my old Sawyer counter-balanced oars. Hope this helps. Additionally, some have resin handles, some have wood. I've seen the wood handles break off flush and they're a pain to remove and replace.