I tried using a Vanilluxe. It was a floating double scoop of ice cream, what could be more awesome? Apparently pretty much everything.
I caught a Vanillite going through the game, but its moveset was awful and it was weaker than everything else around it. I put it on hold until the post game. There, I went through the E4 with the Exp. share a few times until it evolved twice. From there... it was still nothing special. It's learnset consists of ice moves, normal moves, and Flash Cannon. All of its stats are pretty average besides Special Attack, but with only Ice Beam and Flash Cannon and low speed it's not gonna take a whole lot down. Such a cool Pokemon that just doesn't reach its potential, pun intended.