I have the 4X sliders and they have been good except for I bent the passenger side one at the kick out. In my opinion, they need bigger gussets. I had some 1/4" thick gussets cut out for me and I'll be adding them in to prevent bending these sliders again. Luckily my door still opens but I swear its a fraction of a millimeter between the kick out and my rear door now. The kick out is very functional though and after owning these, I would never buy sliders without a substantial kick out.
Heres some pictures of the damage from the bent slider. Granted, I do wheel my stuff pretty hard. My ARB bumper has flexed into my body and caused damage as well (replacing it). My only piece of armor that has been rock solid is my 4XI rear bumper, which I highly recommend.