I have heard mixed things about the revolvers. (obviously) Some rigs they work and work well but others it can be more of a headache then anyhting else.
What your asking about are 2 different items. The revolver shackle is designed to not only twist but drop as well. The Johnny Joints only allow for twist. I don't know that it is fair to say "witch one is better" I do know though that the Revolvers require very little maintenance, the joint "does" wear out and needs servicing from time to time.
Would I run both, yep but only on the right rig. I have a "missing link" shackle in the rear now (drop shackle) I like it.
Stewy