First of all a fifth is 757 milliliters or 752 depending on who you ask, so they're obviously not talking about the traditional 1/5 packaging that some of us olds grew up with, back when standard Jack was 86 proof. I know the legacy editions have been 700 ml in the past, so this is not new. Right off an interesting aspect is a bit of the iron water on the nose, the one normally associated with all things Dickel, seems to have got through the filters in Lynchburg. Certainly less pronounced than Dickel, but it's there however feint. The nose also offers up some traditional sour(mash) the part I personally like best. The high corn sugar is evident and early, just as you would expect, the char residue taste that is so distinctly JD, is a bit less in your face. Oh it still has that rough edge of char on the way down. The shorter cutting to 100proof is easily noticed with the extra corn syrup sugars and I find it a bit mellower on the finish, maybe a by product of some extra aging. This is a bit reminiscent of the JD Century offering. As only a rare imbiber of Jack, at least outside of the barrel rye which I will drink daily as it's really that good, this is clearly an improvement over standard and legacy edition Jack, the real question is,, "minor improvement" or "major upgrade". One thing I would insist on is this upgrades the JD line up, much like their Rye editions did. Cheers!