The great agave distillates
In general terms, one could consider Tequila to be a type of mezcal, since it comes from the cooking and distillation of maguey. But no, each one is unique. The main differences that make each one a significant drink lie mainly in its origin and elaboration.
Mezcal is a pre-Hispanic drink that can be grown in nine states with the Denomination of Origin (Oaxaca, Guanajuato, Guerrero, Durango, San Luis Potosi, Puebla, Zacatecas, Tamaulipas, and Michoacan). In these Mexican states, there are about twenty species of mezcal.
Tequila, on the other hand, is from colonial times, and the agave with which it is produced is exclusively the Blue Tequilana Weber. The Denomination of Origin of this one takes place in five states: Guanajuato, Nayarit, Michoacán, Tamaulipas, and Jalisco (cradle of the Tequila).
Tequila has an industrialized production process, regularly with steel machinery, where it obtains a neutral flavor. And only 51% of agave juice is needed in its elaboration to be considered tequila. While, the smoky and earthy taste of mezcal, is due to its artisan process, to the baking in earth ovens and fermentation in wood vats, also, this one regularly is 100% agave.
Of course, it does not mean that one is better than the other, without a doubt, the quality in both will depend on how they are produced. You can find a 100% agave tequila or mezcal that is only 90% agave and has undergone a process that has removed the distinctive smoky touch. This comparison does not result in which is better distilled; it only indicates the differences between one and the other. The choice will always depend on personal taste.