Who out there has an opinion on TTbike vs Road bike for the hilly port mac bike course

It doesn't matter whatever you own get set up on it correctly train properly and then you will have the best chance of riding the course well. The reality is most triathletes who own a road bike don't have a typical road set up anyway so just train on hills and your long ride on the bike you will race on, if you are lucky enough to own two, this way you are prepared and it will be easier. the other fact is that while the course is challenging and tougher than Forster was it is not like there are mountains to climb on the course most of the hills are under 2-3min to climb as many even less than that and some of the longer ones are still big chainring ridable.
Now getting your set up right for the run,well that is the smarter thing to work on as the run is tough

B+ is right - it's all about being properly set-up, and comfortable on your own bike so you're ready for the run-leg. Sure the bike leg is tougher than Forster (stats seem to suggest it's about 10-15 minutes slower), but really, the hills aren't that bad. They're a little steeper than Forster, but we're not talking le tour stuff. Most hills are between 300-500m long at most.

What's more punishing is the run leg. It's much tougher than Forster's course (if we're using it for comparison), and requires you to be as fresh as you can be when you jump off the bike. IMHO, your bike should be set-up to maximise your transition to the run leg.

Admittedly, I might have added flame to this fire by commenting that Melissa Ashton was tossing up between tri-specific and road-specific bikes prior to IMOZ in another thread. But hey, she's a pro, has the ability to be a competent rider on a quiver of bikes, and can relatively easily adjust her training to a specific course if needs be.

For those of us who own 1 bike, and work full-time and raise a family, you make the best of what you've got. If you were only ever going to train and race for IMWA in Busselton every year, you'd get yourself a TT bike. For Port Mac, you'd be fine on whatever comfortably gets you around the other tri-courses you compete on.