Similar thread worth reading <a href="http://www.pprune.org/cgibin/ultimatebb.cgi?ubb=get_topic&f=12&t=006290&p=" target="_blank">here</a>.
I think you should spend your time looking for a healthy compromise between an excellent instructor and a friendly school environment.
If you want to be a commercial pilot then you're simply wasting your time at the majority of privately owned flying schools (especially in Sydney). You must associate yourself with a school that has some sort of ownership, affiliation or association with a Charter Company or airline. In the absence of such a school, you are best to source yourself an instructor who can be your link to a working GA Charter Company.
Call up some larger charter companies or regional airlines and ask them if they have a preference of flight training establishment. Most charter companies will lean towards a particular school when recruiting. Ask the Chief Pilot to recommend an instructor or ask if they do any part time teaching themselves... they may well appreciate the time away from their desks <img src="smile.gif" border="0">
You mentioned Illawarra Flying School. Their senior instructor (Anthony?) is also the Chief Pilot of a Bank Running company. This is a link certainly worth investigating. These sorts of associations exists everywhere but you have to find them...
A big problem with the current training climate is that a good portion of the experienced and quality instructors have been sucked up by the airlines leaving the industry dry of any real knowledge. To make matters worse - the experienced guys in some cases have spent their entire careers at one establishment leaving them blind to different ways of operating.
Don't fly with an instructor who hasn't had any commercial exposure - especially if you want to fly commercially yourself. It's crazy that a grade 1 instructor can teach a commercial syllabus without ever actually having done any charter flying before in his life! Bankstown is littered with senior instructors that have never flown 'professionally' before so it's very important to shop around.
Find an instructor that is qualified to take you through your elementary training to Multi IFR. Although there is some merit in occasionally flying with other people, your instructor should remain with you for the entire duration of your licence.
I agree entirely with
john_tullamarine's excellent post! Don't be fooled by bright white shirts, a fancy web site or a glossy front desk. There is so much more to a flying school than your first impression.
Good luck.