Welcome Cam, from me, if doing a lot of touring camping, definitely go for gal chasis and powdercoat tub as a minimum. Never been involved with an Aluminium tub, but hey, most caravans over the years were alot aluminium so someone will have a view.
My only other tip from reading this forum is a lot of people research and buy their ultimate dream CT, but then seem to sell and upgrade down the track as you learn what works best for you. So in this vein, buy with a view to resale value somewhere down the track and Aussie Made and some of the good imports should be considered.