mrkmitch,
Of course I have no knowledge of ISOMs, but if I did, I would say in my opinion there is definetly a difference in the same brand from factory to factory. (Quality control, variation in blend or what, I don't know??)
It also appears that there is considerable differences even within one brand and factory depending on dates.
I would love to find a chart, similar to wine charts, that list the various date codes, factory codes, etc. that "experts" have agreed are superior and recommendations for needed aging for those various codes. (IE. smoke now, age 5 years, etc.) I have seen some books that list some of this data.
Until then we all must do our own research. (For the sake of expanding knowledge only of course.)
Many reports I have seen say many ISOM brands blends have evolved to a milder profile since ~1995 maybe to match the tastes of the target markets.
There are still some who produce what appears to be the "old style" blend of 10 years ago. IE. certain Bolivar, etc.
Would be interested in what your research is finding.
lgiffin999 at aol dot com
DED