Yes, what Kitten said. The other thing is, Aussies are kind of a hybrid between the two styles. I rode in an Aussie for a while and LOVE them. More secure than english for trail rides, but more comfortable than western for hubby and I. We both have knee issues, and the pannels on a western saddle stirrups just hurts us far too much. So, for trail riding, we prefer an aussie saddle.
As to what type, it depends on your requirements.