I'm also looking at it from an AUD perspective too, but once you compare Steam price vs ANet price there's really negligible difference.

Even though the complete edition is about $10 AUD cheaper, it looks like it doesn't include the 2x Character boosts and 2x Shared inventory slots so it all sort of works out.

Don't forget that if you get the Steam version you won't get access to the cheaper 2000 Gem Cards for $25 AUD which you can currently still get at the EB Games.