It really depends on what you intend on doing. If I am looking at a helmet that is a full face type, and I have a specific design with elements I want to fall in certain places, I would say the 180, and it will be at least 3 pieces, tastefully hidden in the artwork. If I am looking at that same full face helmet, but the design is very generic and elements call fall where they like, I'd use 380 all day.
I've used both, done full face, skull cap and kids baseball helmets, and even though the 380 conforms easier, I like the ability to heat the 180 better and it still retains it's strength.
Just my opinion.