In reply to JimR: I thought about getting the larger sizes a while ago so had a play with them and did a bit of digging into all the reviews of them I could find. I certainly didn't find any evidence of concerns or complaints about the robustness and they look very well designed.
Over the years I've had the wires go on an older Camalot 2 and on three larger DMM 4CUs (admittedly over 9 years of use) so personally I am perfectly happy to give Kevlar a go as an alternative.
I'm sure someone with more direct experience will be along to post shortly.