I flew with ATFC from 2008-09. They were by far the cheapest flying school at Parafield. This is because AFTC is essentially an instructor farm for FTA.
I flew 3-4 times a week with no issues in regards to aircraft availability. However you will swap from the Grob-a and b quite a bit. Also I had 2 instructors during that time as one left to FTA. I think they leave for FTA once they have a grade 2 rating.