Well it looks like I'm on my own here. I actually prefer going via Sorrento first. I've done the ATB 6 times. The first 3 on a hybrid and the last 3 on my roadie including the 250 both ways. My reasons are as follows.
1 - You get to fly along Beach Rd with little to no vehicular traffic.
2 - You get to see the Bay nice and early and as the sun rises.
3 - Faster trip to the ferry.
4 - Little to no wind most of the way.
5- You get the few hills over early when you're fresh.
6 - Beach Rd too busy in the afternoon.
7 - Usually get a tail wind (SW) up the highway past Geelong.
8 - Fewer bikes to contend with up the highway past Geelong when you have to use the emergency lane. Safer IMO.
9 - Once you're past Geelong all I'm interested is finishing so don't notice the scenery, boring as it is.
Given all that I still alternate directions. This year I'm doing it via Queenscliff on a tandem, just for something different.