I just checked my tickets from my flight on virgin in march. Syd-lax in Y+on points + taxes $390 on our return in J it was $309 so this reduction in taxes is hugeWith QF the taxes are mainly QF's own extra charges which they put in addition to the fare whereas VA have the bulk of their surcharges within the fare which is what makes their points scheme so much better.
For example look at the QF and JQ Honolulu flights and compare the 'taxes' - the QF taxes are nearly as much as the JQ cash fare!