Are the 2 planeswalker sets from Amonkhet balanced?
In the official announcement post, the following line is mentioned, from which you could deduce that these decks are meant to be played against each other:


  The decks are meant for newer players but can be fun for anyone to battle them against one another.


Of course, whether decks are balanced in practice is always questionable, and other than the decklists also depends on the skill of the players which are playing them, and their affinity to the deck's theme. Generally, you should end up with a somewhat balanced deck, however - very likely more balanced than any two random decks you would construct from your card pool on your own.