I much prefer full seat breeches, I just feel more comfortable and secure. I ride dressage so I have the option but if you were in hunters and equitation you wouldn't have the choice. I believe you can wear them for jumpers.
I like full seat breeches. Both are comfortable but sometimes the knee patches just bother me a bit because they are only on the knee. I find that full seat breeches have more grip and I think they just look better with tall boots! But it's really your preference what you pick.