Round wheels definitely climb better for slappies, but sometimes easier to overshoot.
As far as pinching goes, I feel like a round wheel is better on a sharp edge, but if you're crooking a rounded curb or concrete ledge, sometimes a square wheel holds it a bit better. If I 5050 a round rail on round wheels the cross pinch feels more natural, but with really square wheels theres a bigger chance ill end up doing double heel lock.
Flip tricks definitely work different. Recently went from 55 og classics (basically didn't shrink at all) to 55 classics and scoopy tricks felt immediately different, had to adjust and scoop my tres less pop down more instead. All straight flip tricks also felt like they worked a little easier. Not sure what the cause is, but probably not weight since 55 classics and og classics weigh basically the same, and its not height, but its definitely noticeable if you pay attention to it