Unless DL significantly undercut QF prices, I think that if I plan on heading to North America, I will continue to stick with QF on the route. With DL entering the route however, this probably reduces the chance of SQ or EK starting a SYD-East Coast operation. Decent amount of competition now
QF
VA
NZ
DL
HA
FJ
AC
UA
TN (to a lesser degree)
....and JL/KE/OZ/CX for those willing to stop in Asia.