TalKSicK333Hey, sorry for the late reply.
It comes down to your preference, because there is a trade-off.
Sheepskin is less sticky than the stock pleather, and if you are going to sweat anyway it is easy to wipe clean with a damp cloth (don’t soak your pads! It breaks down the memory foam). However, it will still get hot because it is still a sealed earpad, keeping sound and hot air from passing through.
Velour is a cloth. Like a tee shirt, it doesn’t trap heat and allows you to stay cooler, and it never feels sticky. However, it isn’t sealed so you will lose some isolation (some sound will leak in or out, but not as much as when you aren’t wearing headphones), and if you are going to sweat anyway then the sweat will get into the pads. We’ve used Velours for years, and even our hardcore gamer dude (when he plays hard, he says he’s “playing sweatys!”) gets several years out of his velour pads. He prefers velour or hybrid pads.
Fenestrated Sheepskin and Hybrid pads are kind of in-between options. Fenestrations are little holes, which allow some heat to escape, some treble glare to be absorbed, and still a good bit of isolation and you can still wipe the surface clean. Hybrids have the fenestrated sheepskin on the “inside” facing the sound, solid sheepskin around the outside to keep it sealed, and velour where it touches your face.