I run them in the rear of my rig, been in there 1 year so far without problems. I like the idea of playing with the different inserts to change the stiffness. I played with the dual rate adjusters on my coil overs to make sure the spring rate ramps up so as not to rely on the bumps 100% to stop travel. I run a rear TK1 sway bar that also helps to keep me off the bumps at full flex. They seem to come into play mostly when I drop the rear in off a big ledge. I honestly don't think would live if you needed them for every little bump you hit. That foam is gonna break down pretty quick from what I read. But for stopping wheel travel right at max flex, they seem to do the job.
The upside is that in the future if I decide they are not up to the task, I can swap in some proper air bumps into the same cans. I chose them during my build because of the cost, parts were adding up quick. I made a few concessions during the build, things like this that were easily changed.