I have had nothing to do with Ad Astral, they do have a very good reputation.
Johnson's on the other hand, I completed my Instrument Rating there, they provide accommodation, its in a Baron in a quiet airport, there are all the approaches you will need near by.
PMQ is a lovely town, lots of great things to do after hours.
Jamie, Anne and their first born Kev are awesome people.
I would personally avoid big aerodromes, Perth specifically, I'm not saying that because Ad Astral are there, again they have a very good reputation. Perth is a very very busy airport.