My first pair of adjustable trekking poles (REI Peak UL) made me into a fixed-length convert. Just the initial process of extending them to the same length, screwing down the expanders, etc. was enough for me, let alone stopping to change lengths every time the terrain changed (of course it didn't help that these were the first-gen ones with the balky locking mechanism). So I returned them and used the refund as a down payment (ouch) on a pair of the previous generation of BPL Stix. I figured how to choke down and palm the grip on uphills and downhills which made a lot more sense to me then stopping and playing with expanders and wrist straps.
One of the things I like about ultralight backpacking is the simplicity and low-fiddle factor. Fixed length poles delivered that to me in spades, plus leaving off the expanders and associated ferrules saves a ton of swing weight, which makes placement easier, etc. The Stix are solid as heck, never felt hesitant for a moment to put all my weight on them, pole-vault, etc. Just gotta be careful not to wedge the tips, like with any pole.
Never had a problem with tarps, since I just use a clove hitch in the guyline over the inverted poles. With a tapered profile it doesn't slip at all under tension, in fact the more tension you put on it the tighter it gets, yet you can still slide the hitch up and down if necessary. The SMD Gatewood is a little trickier, though.
I put some heat-shrink tubing on the bottom sections of the shafts to help with rock abrasion.
A. 4' poles strapped to your back have a way of finding low-hanging tree limbs. But they're so light you can just carry them in the flats, and when if I have to scramble it's usually over rocks with no tree cover.
B. The old models didn't have a conventional wrist strap. At first I enjoyed the feeling of not being "strapped in" which I disliked about conventional poles, but after a long day the hands definitely get a workout. The removable wrist strap on the new ones seems like the best of both worlds. of course, the wrist strap might interfere with the ability choke up / down on the grip.
C. Not very convenient for air travel. Rather than check them separately I picked up a new pair of the Peak ULs I started with, for times when I really need the collapsibility.