I have two aussies, that are different as nite and day. My female is high energy, demanding, and requires ALOT of mental/physical stimulation or she is a beast to live with. She hasn't got a serious bone in her body, is quite a comedian, loves to show off, and has quite an independent streak when it suits her. She is out of a mix of show lines/working lines with alot of Hall of Famers in her background.
My male out of working lines, has no problem lounging around all day, but bring him out to work and he will run/work "forever". He is a serious dog, and takes his play/work very seriously. More velcroey, less independent, can be "male" aggressive, bossy, alpha type personality. Also has displaced aggression.
Those describe mine, when I first got into aussies, I saw to many that were dog aggressive, people aggressive, just not good temperaments. Thankfully, I can live with and take mine anywhere with no problems.
They need loads of socialization, they do need a leader, they defiantely can have an independent streak. In other words, if they don't wanna do it, they are NOT going to do it. Positive training works great with them, in fact I find clicker works great, they are good "trick" dogs, smart as whips. negative /punishment type training will shut them down and make them even more determined to "not" do whatever you are asking. To much repetition in training can bore them.
The merle is a real cutie by the way..Be prepared to spend ALOT of time with an aussie, especially the higher energy ones.
Diane