Hi @jmaunsell ,
Telescopic have a long history and will do the job well. I'd consider collapsible (Z-folding) if weight or collapsed size are an issue. If you travel you may find that telescopic may not fit in medium or smaller sized luggage.
Carbon fiber is lighter but not as strong as aluminum. Metal tends to bend if stressed while carbon fiber tends to snap. I prefer carbon fiber collapsible (by Leki) because I travel. But I've broken one pole when I tripped and fell on it.
Pay some attention to grips and straps. Try a variety of styles to see what feels best. In my experience Black Diamond straps aren't durable whereas Leki are.
All telescopic poles are height adjustable. Most collapsible poles are height adjustable but some come only in fixed lengths (e.g. some BD.) I would avoid the fixed length ones. It's important to be able to slightly shorten poles when climbing uphill and slightly lengthen them when going downhill.
One more thought. I don't know how rational this is. I've never seen anyone else discuss it. But it's occurred to me that aluminum poles make good lightning rods. If you intend to do a lot of hiking in the mountains, especially above the tree line, I'd avoid them. [Added: I did a quick Google search. It seems carbon fiber is a conductor too. Hiking poles only act as lightning rods if you hold them above your head. Otherwise assume you are the lightning rod. So poles or no poles, if you find yourself in a lightning storm seek shelter immediately. If you're on or near a peak, get down ASAP.]
one or more gifts or other benefits from the co-op.