Maybe if there is a regional difference it has something to do with coyotes getting wise to what they have been exposed to from trappers and associate that particular thing with danger????

I'm not a huge believer in coyotes having " different tastes" so to speak from one region to another unless they having been educated to a particular thing from over use by trappers. I will admit i haven't trapped other areas and will admit my opinion is open on this subject based off my experience. I will also say I've seen really good formulations shine no matter what region they are used in. What I think may be the biggest contributing factor to the regional argument is how hungry are the predators from a given region are and how cautious they are. A really hungry coyote is going to be by necessity bolder along with a completely naive coyote and therfore a less attractive formulation may be fairly successful and also in these situations it might be more difficult to see much difference in the attractiveness of different formulations.

Again lose theory based purely from info I've gathered from visiting with other trappers in other regions and comparing notes.

Another side note about differences in attractiveness of baits, lures and ingredients, the individuals skill as a trapper, ability to read and interpret sign and their pinnacle of what a good attractant should be are all factors.
One person's idea of "good" may not be good enough for the next guy.

Just food for thought that might open the door for more conversation.