Better with rifle or sidearm?

I've been told and it seems to hold true at least with the folks that I've interacted with lately, that people have an affinity for and are a better shot with one or the other: Rifle or sidearm.

Until recently I would have said I was much better with a rifle. My current A-gunner and I started looking at IDPA competition shooting for a way to stay proficient with the sidearm. My rifle is pretty good, but with all this practice I'm nailing the 45 big time these days. My A-gunner is clearly rifle dominant, seriously good with the rifle, but only competent, not even in the very good category with a pistol.