I have been using Queblok for about 6 years, originally purchased from Capral before Bunnings started to carry them.
After a while although still functions well in my van for storage is started to loosen up after about 1 year, The cause I isolated is the plastic inserts start to loosen up from vibrations. Then the aluminium also starts to flare out.
The concept is great and very very economical but I would worry about tolerances changing after a while.
I've also been using the stuff for over 20 yrs, long before Capral and Alcan. The manufacturer has changed names a few times over
the years, as well as the name of the 1" tube system. My entire workshops, including most my home are made from it.
BUT I do agree about "ageing". If you have ANY vibration, it WILL wear with time, sometimes a lot. PLUS, I recently made a new bench
using about 80 fittings, Al drop saws, polishers etc AND the fitting tolerances were all over the place !! Some tight as heck, others
so loose that I exchanged them. I think QC has suffered over the years. If you check the video, EXTRA screws lock the end
caps in place. They WILL SHAKE loose if you don't take precautions !!