I think it is just personal preference. I prefer the judo style gi (even in the summer). I like the weight, the way they feel and they do soak up sweat nice. At one point in time, Chiba sensei would only allow people to wear judo style gi. As for the judo pants, I think the extra layer helps with durability with all the suwariwaza. I would go through pants a lot faster if I didn't have that extra layer (unless you get really thick canvas karate pants). Either way, whatever your sensei says comes first, then your personal preference comes into play.