Umm the downside is that if you don't win, you are responsible for their costs and legal fees. On the upside if you do win, they pay yours. Or 60%, I'm not sure what the exact rules are.
I am 12 months into a Fair Trading / CTTT dispute with my house builder and am $25k down in expert and legal fees so far. $400+GST/hr adds up reasonably quickly. When we win we stand to get 60% of that back.
As far as the actual process, there are one or more prelimianry hearings, each a few months apart, where you and the workshop state their case. Then a hearing to make a decision at the end of that. The decision is made on hard evidence like paperwork or expert reports (eg from an engineer). Verbal claims or input are not really given any weight.
pm sent re my experience with a workshop and CTTT