The Westpac Earth Black earns 1.5 Qantas points/$1 on the Amex, and 0.625pts/$1 on the MasterCard (1.5pts/$1 on foreign transactions).
The Westpac Altitude Black earns 3 Westpac Altitude points/$1 on the Amex, and 1.5pts/$1 on the MasterCard (3pts/$1 on foreign transactions). Looks good on paper, but as an example, 2 Altitude points equate to only 1 KrisFlyer mile (Singapore Airlines). I believe the earn rates are similar for their other airline partners - so it essentially earns the same number of points/miles as the QF card, but in their various airline programs. Note that new customers cannot earn Qantas FF points with the Altitude Black cards.