I have the RK 3 link kit, and have wheeled the shit out of it for the last 6 or so months in mainly big rocks. All components have held up well. I actually just pulled the arms off today to disassemble the joints to check for wear, and everything looks great. The Krawler joints have held up fine.
It really does articulate extreamly well, very smooth, im running 12" shocks but could run 14's if i really wanted too.
The arms work well sliding off rocks & for sure have better clearance than drop brackets. The brackets so far are super solid, they have taken some decent hits and beside some rock rash are straight & true.
I dont DD my rig but i do drive to trails & on the FWY it seems just as good as when i had 4 link short arms. (as good as a lifted,35" tires,no swaybared XJ drives).
Honestly i think value for money, its a great kit. JMO.
If you do get it, make sure you disassemble all the joints & grease them before you intall the arms. Mine were basically dry when new.