If you’re on a deadline, stick with AE because it’s what you know.
But if you have some downtime, dig into Motion and learn it. You’ll find that there are scenarios where Motion can bang out some things much, MUCH quicker than AE. When you get to the point where you’re competent with both AE and Motion, it’ll be obvious when you want to use AE and when to use Motion.
Kind of like the difference between a biscuit joiner and a dowel jig. They both do essentially the same thing, but there are particular circumstances where each is a better choice than the other.