I think RE's design predates RRO as a company. their drop brackets have been around forever it seems. like, they were an option back around when I first got my truck. waaaaaaaaay back when there were 2 options for drops, and RE was one of them. I forget the other. something a bit cheaper.
I assume we're all talking about these ones? I see from the install pics, that they now offer a reinforcement bracket for XJs. that's good. they probably have been offering that for years now though, it's not like I've researched drops in a while.