Camper trailer annexe poles

Like everything, you can get different grades of poles based on your budget, so the more expensive ally poles are probably better than mid priced gal options.

There are many wall thicknesses, grades and tempers of aluminium too, so its a bit hard to say that aluminium will be better overall. Its probably safe to say they will be marginally lighter though.

One thing about bare aluminium, all the poles bundled together and rattling around will get a nice coating of grey dust over everything in the container and whoever handles them. That can be a bit of a pain.

Scott : presume you are trying to save weight ? As mentioned... obviously best option would be to buy top quality . Vertical poles won't be a problem in the short term but the horizontal ones could be ones that bend or break from holding up the weight under adverse conditions rain and wind . IMO in the long-term good quality steel are far more reliable ..
When we are doing a long trip & moving regularly we don't take the annexe all the poles saving weight and space.

Had aluminium poles in our Kimberley Kamper for 10 years without any issues with them at all, they would of rattled around in their box over many many klms of corrugated roads in that time frame. Work fine when beach or bush camping, haven’t damaged one in all those years.

For the last 6 years we have had a Gordigear soft floor tent on my homebuilt trailer.
All aluminium poles and bows with "griplock" fasteners.
No screw in tees for me.
Beach, bush and bulldust, no problems.
A Lightning Ridge dry storm or a Straddie east coast low. No damage.
And no dust. Except bulldust. Can't keep that out.
Rod.

Aluminium poles are fine, better than gal I think because of significant weight saving. However be sure to buy anodised ones. My experience is with the ‘Supapeg ‘ brand. They will be more expensive, but have 2 important advantages over cheaper offerings. They will not make your hands black every time you handle them, and the twist lock mechanism will be more reliable. Built in longtitudinal ‘grooves’ increase strength I think. I had Gal poles for years , then cheaper aluminium poles & now the supapeg poles.

DIY: Two, five foot lengths of PVC pipe that fit snug into each other. Drill one 1/4" hole 3" down [for bolt and wingnut] from the top through both pieces then take out the inner tube and drill holes every 2" for 2 foot in the inner tube. Drill a 1/4" hole in a end cap for the inner tube with 3" bolt and nut and heat shrink over the thread of the bolt then glue on cap. You can place a cap on the bottom for sand. Adjustable annexe pole that will last a life time. You may have to get electrical PVC to fit snug into Bunnings PVC. Choose diameter PVC to suit yourself.