In reply to mwerner: I've found my sprung ones a little disconcerting at times - if you put a little too much weight on them (as you sometimes inevitably will) you can feel the pole shift down a little, and it can make you think the pole is about to contract in, and so can reduce your confidence in them
Another thing to consider, and I don't know if anyone else has experienced this, but I'm also not too sure about twist locks. Mine have this, and I occasionally find one of the sections shortening slightly under load, and so requiring readjustment to keep them at a good length. Maybe this is just a problem with my poles, or maybe its the case with all twist lock setups; I don't know.