You cannot judge a book by its cover, or in this case, by its breed.
You'll have to ask the seller about the horse's individual personality to see if the horse is the more laid back kind.
For example: I have two quarter horses. One is going to be 7 and one is going to be 2. My 7-yr-old is like the energizer bunny. Load of energy, never wants to stand still, etc. Whereas my 2-yr-old is like a sloth. Lazy, quiet, easy going. Nothing bothers him. Both horses are bred to be good barrel horses. But they are completely opposite.
You simply cannot generalize a breed, because each horse is so different.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.