I've ridden in both jeans and breeches, both English and western. I don't hate riding in jeans. I can do it, and I have, but I much prefer breeches, regardless of discipline. I just like that the breeches move with you, and breathe better. I sweat and get overheated when I'm exercising, and jeans just get uncomfortable for me when I sweat. They stick to me, and don't breathe at all. They're a bit restrictive as well, especially once they start to stick. Though I don't like wearing jeans much at all, in any situation. I tend to wear sweat pants, yoga pants, or exercise shorts whenever I'm not on a horse.