I've used original black rubbers on posts.
I've also used Cliffy's colored Urethane post sleeves.
Tried the Superbands sleeves and promptly removed them
Currently considerng trying out the Titan brand Silicon post sleeves.

In addition to the difference in recoil, the main other thing I've noticed is that a shot that grazes a post will behave quite differently, depending on the type of post sleeve used.

In my tests, the original rubber sleeves are the most forgiving.

The Cliffy sleeves and the Superbands will measurably slow, and sometimes all but stop the ball, even when the ball just grazes one. If the post grazed is at the base of a ramp, as they often are, your shot may not have enough power to make it up the ramp.

That left me wondering... Has anyone ever thought of creating a post that has a rotating collar around a stationary center shaft?

The rubber/urethane/silicone/whatever would then rotate rather than slowing down the ball on a grazing shot.

I'm not suggesting bearings or anything that drastic. Just an ultra-thin metal sleeve around a metal post that ends up being the same diameter as a regular post today?