I have some installed in a set of bias Treps. Definitely much lighter than any traditional beadlock. They have some other unique advantages over a traditional beadlock, but most guys with typical trail rigs don't care/won't notice. They are a pain in the ass to install and I don't think they are really worth it for a recreational rig (especially a Subaru on 31s

). Lots of guys in the EMC classes are/were running them.
I guess all these guys saying double beadlocks are pointless have never burped/lost an inner bead.