I visited Oaxaca in Mexico last year and was totally blown away by the quality of the small family-run Oaxaca distilleries dotted around in the hinterland outside the city. Del Maguey are one of these, and the quality is exceptional, they are all made from 100% Espadin agave and made the traditional way, as they have been doing for four hundred years. The smokiness in Mezcal comes from the giant fire pits that the agave are cooked in. It's sort of like a cross between Tequila and a really peaty Scotch. It's hard not to love the product when it's made in such an ancient and hands-on way, there are no big companies with automated systems churning out a suboptimal quality product with Mezcal.
Here's an image from my trip of the agave being broken down before being put into the pit - Charlie Stein