Comparing to Cognac, Armagnac is more vivid but less refined. I like Armagnac too but have never systematically approached it. Unlike Cognac, Most Armagnac are small production and lesser known.

In case you are interested in other kind of brandy, there is Calvados from Normandy that use apple instead of grape. I don't think Calvados is up to the level of Cognac or Armagnac but it is certainly interesting. It is very good to have after dinner. Many desert recipes also call for Calvados.

Grappa as in Italy is distilled with grape-must (after-product of wine making). It's also very interesting - similar but different from Cognac. Grappa is more refined than its French cousin, Marc, which is made in the same way but has very earthy taste.