Yes there are temperment differences between species. My experience is limited to pretty much water moccasins and copperheads, the only hots I encountered in the wild when I lived in texas and louisiana.

The copperheads never seemed defensive, they pretty much ignored people even if you got close.

Water moccasins ALWAYS seemed defensive if you got close. They either bolted or struck a pose with their mouth open. It's a pretty awesome sight, but I have a VERY healthy respect for them.

There are always exceptions to species' reputations, and my dealings were all with wild animals in their environment.