The crank mounted disk is a bad system 
(Sorry.)
I’m one of these guys who prefer having an inner-board disk as it’s easier to work with: the disk setting doesn’t rely on the crank which is IMHO far easier when you have to change your cranks for example. And I have had less issues with inner-board disks - which I have used throughout time on 3 unis.
I don’t think it is true anymore. It was, but now other have filled the gap. IMHO Qu-ax is a better brand now with their #RGB series. They are theoretically lighter and I know a single person who have had issue with it. Well, it was @mowcius 
In any case, KH is still a great brand and you shouldn’t have many issue if you go for it!