I've always avoided corn-based whiskey and preferred rye. Generally, I avoid any US corn products where possible.

Mexico takes their staple crop seriously. They've banned the Bayer/Monsanto engine corn. When making tortillas, I use Mexican masa harina. Strangely, most Mexicans here (US) use the Azteca brand, which is about as Mexican as Moses.

I'd definitely go for some heirloom corn Mexican whiskey.