traditional wire jobby or on of these alloy sheet curled into a tube type things?
is carbon just for rich weight weenies or does it have benefits?
any make superior?

Carbon’s just for show, and will break when you drop the bike.

I know someone who won a Carbon one and he’s still got it after 3 years or so. Think it was a bonty one if that helps. I just buy cheap ones as I dont use them often – i.e. take them off when not needed.

Carbon – Can be brittle, doesn’t hold bottles that well.
Alloy wire – Works well enough, marks bottles, wears eventually.
Ti wire – No marking bottles, no wear, no corrosion, light, expensive.
Stainless steel wire – No marking bottles, no wear, no corrosion, light enough, not too expensive.

SS best IMO.

I had a Ti wire (actually tubing) one snap.

I’ve got a Bontrager side entry cage on the Pitch, which is very handy if there’s not a lot of room on your frame. Very secure too, I had it on my Yeti 575, under the down tube near the BB, for the whole of the TransWales and it held a full bottle fine

Specialized Rib Cage is my favourite, holds a 750 ml bottle on my Anthem x no problems.

My fancy carbon one lasted about 2 months before I snapped it.