My JK tuned Fox resis 4"-6" seem to do pretty well absorbing once they have warmed up a bit. When I first got them they felt harsher because I was pretty light weight. 37s, with no fenders, no rear bumper, no winch, no top, and no spare. But now I have fenders, exoskin, sliders, tire carrier, spare, roof rack, RTT, and a winch. This definitely softened the ride up. I believe the progressive springs that come with the kit are meant to have a little weight on them for ideal comfort.
I do a lot more crawling and notice how awesome they soak up river rock when hitting faster portions of the trail, but if you are looking at getting some higher speed wheeling in, maybe look into some hydro bumpstops.