Feels like we've had this topic several times already but sure, why not reply to it again.
Anyway, my main playthrough of X had me choosing Chespin. It's my favorite of the three starters by design, and it did do me pretty good even if it wasn't too good against any of the Gyms I came up against. But one of my challenges, a very difficult Wedlocke, had me picking Froakie based on my ID No, but it became a Greninja and it lived all the way to the end, as a Frogadier there were a couple times where it came super close to dying but it didn't. It was quite good for the team.
To say the least I really like all three starters in this game, they're probably my favorite batch of starters yet.