I'm not afraid to admit that my current choice is Popplio, and yes, it's out of contrarianism.
Me and my friends (about ten of us who play Pokemon) tend to make a big deal out of new generations during the first month of release - it becomes a bit of a competition, and there's an unspoken rule that for the first week or two at least, nobody goes to GTS or Wonder Trade etc to nab an unfair advantage. I'm pretty sly and underhanded, so I'll always grab the game with the lesser popularity (most of my friends are getting Moon so I'm grabbing Sun) and the starter least chosen (I'm the only one among my friends choosing Popplio).
The benefits are obvious. By having the rarer of the legendaries/version-exclusives and the least chosen of the starters, I stand to benefit because I hold resources that are scarce. X and Y fucked me up in this regard because for the first time, that cunt of a """""""rival"""""" just gives you a Pokemon egg for one of the other starters once you complete the game. Dumb bitch.