An alfajor is, in theory, a simple thing. It's a dessert sandwich. The argentinian alfajor is usually filled with dulce de leche, which means you just can't screw it up. Even a bad alfajor is going to be good.
Yes, there are some regional alfajores filled with other stuff. Don't pay any attention to those impostors. They are hipsters wearing fake glasses they don't need. What you want is dulce de leche.
But the filling is only half of a sandwich, and a third of an alfajor. There is also the things that surround, hold and contain the notoriously sticky dulce: cookies. Some variants have tried to improve on the cookie by either going soft (cake!) or hard (Milka Mousse), but the real deal is a soft-ish cookie, not too soft (so the alfajor doesn't desintegrate) and not too hard (so it doesn't feel like eating a hockey puck).
There is an impossible tradeoff, between dulce de leche and the cookie. Too much cookie, you are eating cookies. Too much dulce de leche, you may as well get a spoon and eat out of the jar (try it sometime). You want to balance, but the alfajor is walking food, it has to be edible by a 6-year old schoolkid while climbing a tree, it has to be solid enough, and not fall apart, and not cover him on melted frosting. The child has to be able to pass inspection of his hands after cleaning with just the wrapper and his own mouth.
The alfajor santafesino has adopted a minimax strategy, maximizing the amount of dulce de leche per amount of cookie, by using extra-thin "cookies" that are more like crackers, adding multiple layers, and making the whole alfajor thicker. I love it, but it is not for everyone.
The alfajor de maicena goes in a completely different direction, having a tasty cookie that can hardly hold any dulce de leche because it's too friable. Somehow that works wonderfully as well.
Then there is the covering. Chocolate, frosting, coconut, or nothing. Chocolate is bad in summer, melting and making you eat the alfajor from the wrapper as if it were a banana.
But if you have no idea what an alfajor is, which one should you have? I could point you to the most sublime alfajores, which would be life-changing experiences, but I will not. If you tried those, which you can only get in out of the way places, known only to initiates, where could you go from there? It's like your first date being with Sofía Vergara. That would be just leading you into a life of disappointment.
So get a chocolate Havanna. Get a Cachafaz. Get a Capitán del Espacio. Get a tube of Jorgitos. And when you have done your apprenticeship, when you are an alfajorman, when you are ready. Then you will know.
PS: Thanks to Juan Rodriguez Monti for the idea for this post.