Irish People Try American Bourbon Vs Irish Whiskey

The mash bill and location/climate where it’s aged make the biggest differences.

I drank Jack Daniel's Gentleman Jack for years until I tried Jameson's Black Barrel. Now that is my whiskey of choice.
Not enough "o's" in smooth to describe it.

A few differences come to mind: number of times distilled, type of grains, types of barrels used...