Quickest route Bris to Sydney

Interesting, as you say, depends where you are in Brisy and where you are going to in Sydney.

The Summerland way does work well.
See what happens with Tugun now the bypass is going in.
Could save 15 mins plus there, and combined with the new section down to Byron, and still being extended south, it could be quicker soon.

For Penrith / Richmond area from western Brisy, I always found the Newell Highway a better drive, via Coonabrabran, Gulgong, Lithgow and the Bell road. About 20 mins longer than the New England, but a lot easier drive.

Eastern Brisy to north eastern Sydney, Pacific.

I am south west Brisy, so it is a toss between New England and Pacific for east/central Sydney.

Best run I ever had was about 10 years ago from Sydney UBD to my office in inner Brisbane was 10.5 hours. Got every green light heading north out of Sydney at 4:00am and no hold ups on the New England. One 10 min stop at Scone for fuel.

Have to agree John.
The worse part of the trip is heading south from Hornsby especially heading towards the western suburbs.
Vince