This was a great way to spend an afternoon in Oaxaca: you get a great meal, plus knowledge you can put to use back home. And not just the process of making moles / sauces (which you could find in a good cookbook), but his approach to cooking that comes from his experience as a chef. Once you make the seven bases he teaches you to prepare, you're set up to create a huge variety of finished dishes, which he demonstrates by having you make one dish after another: fry some tortillas, add some black bean sauce and quesillo, that's one dish; combine tortillas, tomato sauce and avocado chunks, that's another dish, etc., and they all taste great. He has you do this enough times that you learn to appreciate the creativity and elegance of Mexican cooking, which is the sort of thing it's tough to learn from a book.
Augustin's a very generous, friendly, knowledgeable guy, and he's got lots of stories to share (which get even better as you work your way through the mezcal together). He speaks excellent English, so we had no communication barriers. The class was easy to arrange: he took our reservations over email and picked us up at our hotel. He walked us through the market, answered our (numerous) questions, and shared his home and beer, so it was a very immersive and authentic experience. It's informal and hands-on, and when you're done you'll be stuffed and probably drunk. If you'd rather sit back and watch a demonstration, a la Food Network, this may not be the right choice for you, but if you want to dive in, I recommend it.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.