(It looks like someone updated the Wiki, but didn't actually mention it here, so...)

The T-bus between terminals is now free! That's right - Sydney has now left the ranks of third-world airports where you actually need to pay to transfer between terminals!

The QF or VA buses will still generally remain a better option if you're eligible for them (with the possible exception of D->I where TBus could be faster than the VA bus), but it's good to finally have a free option for everyone.