While visiting the Thompson in BC, the importance of wading staffs became all too clear. The rocks that line the shores there are incredibly slick, so much so that felt is useless - even my trusty carbide tips were like little roller bearings on the rocks. Without a staff, you were sure to take a swim. Rivers like the Thompson drown men easily and the staff is a key tool one must have to fish there. But all staffs are not the same...
Interlocking metal staffs are very light, compact and sturdy. They are kept in a belt-mounted holster while not in use. There are three things to think about here: interlock style, tip, handle. Their diameters are generally small enough not to increase drag against the current. Weight is consistently light enough across brands. Other factors like color play a role but are less critical.
The interlocks that are tapered tend to bind. A better style is the type that uses a straight ferrule, which does not bind. I either case the internal bungee should be tight enough to hold the staff together as much as possible, and tensile enough to easily re-lock the sections with one hand while you wade without fudging with it. The interlocks play the key part in this of course - by holding the staff together as you wade.
The tip - some like a rubber tip to quiet the approach. I would have to agree with that. Other designs use a hard tip, which makes a lot of noise while wading. I assume the tip gets lost a lot, and lodged between rocks. Even still, something to pad the scraping and clacking makes sense.
The handle - should be at a height where one does not need to lean to use the staff. I guess this is a statement on staff length as much as handle style. The straight 'spin rod' style handle works well.
I'm no expert, and would be interested to hear other's opinions on the topic.