TweenService or custom easing style & direction formulas?

I can’t decide which one I should use; TweenService or a custom approach to animating with formulas. The formulas for styles and directions won’t be an issue, however I’m unsure which one I should use.

TweenService will be an easy approach, but using formulas will again give much more control and flexibility. I need some opinions for this.

I’m creating my own personal animating plugin for which I’m asking this…