I was hesitant to pick up the JB Hi Fi exclusive, as the back cover only listed "The Evolution of Bad Grandpa" as an extra, without the features of the US version. The standard AUS version lists no special features at all on the back.
I still purchased it, and happily discovered that disc 1 indeed contains all of the extras from the US release - behind the scenes featurettes, alternate marks, and deleted scenes. And the bonus disc contains a 26-minute interview with Johnny Knoxville.
So this is by far the best version to get, and the current $30 price tag isn't too shabby considering the value.