I have been running them for quite a while and they still work great. I do clean them up and add some grease once in a while but that's it. As for the durability, I would say they have pretty much the same durablity as the regular universal/cvd shafts. I didn't break any DCJ Shafts but i'm way too far from Hara's level
I think i'm good enough for durability testing for you guys.
Thanks,