I have bothIt's pretty well understood that analog sticks are terrible for aiming, it's just something consoles have been stuck with since they don't want to support mouse. There's a reason why every other console shooter has heavy aim assist to compensate for it. But since Splatoon is designed and balanced around gyro, there's no aim assist whatsoever, leaving stick at a heavy disadvantage.
Analog sticks can only control your reticle's velocity, not its exact position. You're capped on how fast you can move to your target. And don't think that simply turning the sensitivity up solves the problem, because then trying to make precise adjustments becomes a struggle. You're forced to choose between speed or precision, can't have both.
Gyro finally offers a real positional input scheme on console. You can move the gyro any distance and your reticle will instantly move to that exact position. Speed and precision are both possible. It's the same principle as a mouse.