I've done a bit of training at both Schofields and whitworths so can't really comment on any of the other schools.
I'd heard good things about Schofields but they're having severe growing pains. They used to be a good club but have turned into another sausage factory as of late. Some of the instructors there are good, others strut around waving their brand new grade 3 rating around like its made of gold. They have some ok planes, but the majority are overworked and undermaintained. Don't believe me? In the past month, I've heard both their arrows on the radio 7 times at YSBK with gear troubles.
If you can get a good instructor there (and there are some), then go for it. However if you're not just a little pushy, expect to end up at the back of a line that never ends struggling to find bookings and airworthy planes.
I've only done a little bit of training at whitworths but have thoroughly enjoyed it so far. The instructors there are knowledgeable and experienced and always go out of their way to answer questions
If you're looking for quality training and happy to move around, I'd steer clear of bankstown. While there are exceptions, the majority of schools at Bankstown are focused primarily on maximising throughput and profit rather than looking out for the student. The majority of instructors at Bankstown are just counting the hours until they can get the hell out of instructing and into a jet job with minimal or no experience whatsoever outside of instructing (ie they've gone straight from their CPL -> NVFR -> I.R.).
Find a school where the instructors actually want to be there and instructing. Have a look at the condition of their planes. Are they looked after and clean or tidy and falling apart. Make sure their instructor(s) have a broad background. While it's always going to be the case that there are instructors out there with 200 hours (blind leading the blind), there should also be experienced instructors there to supervise. Have a look at their booking sheet and see how full they are (can be good or bad obviously).
Have a look at where they get their maintenance done (whether it's "in house" or not). This can be an advantage as you can see the aeroplane "naked" and not only learn more about the machine you're flying, but also ask the mechanics about anything.
What sort of connections do they have? Will they be of any use in getting your first job? Again, be careful what they say to you here. Best to speak to past students.
What is the pass rate and waiting time on their CPL flight tests? Is the CFI a hands on bloke or someone who just comes in every now and again to have a look at things and sign some paper.
If you can, try and spend at least a day at a prospective school, watch how they go about it, and talk to current students. All other things being equal an Instructor who has industry experience and a grade 1 rating will be better and worth paying more for.
There are thousands of questions that you can ask, but the main thing is to be comfortable with the surroundings. Are the instructors and staff friendly, happy and easy to get along with? Nothing worse than having to sit in with a bloke who is **** all the time and doing more bitching about his lot in life than teaching you to fly...............
The best thing to do is after you've narrowed it down to 3 schools go for a TIF with each one.
Take careful note of how they welcomed you, gave you a suitable briefing, gave you much of the stick time, debriefed you, and whether you felt you wanted to train there.
Don't make the decision until after the third flight. Yeah, it will cost you extra for those 2 flights which didn't corrugate your iron, but you will be happier in the end.
Good luck, wherever you end up choosing.