Not me. I'm one of "those" guys who doesn't like adding a "variable" into the hub/wheel/tire function/attachment. I understand that with proper fit, torqueing and maintanence, they can be used safely, I simply don't want add another layer onto regular checklist by having to remove the wheel to maintain torque.
I'd also be concerned about creating a rubbing issue depending on your tire along with the width of spacer you choose.
I'm also not convinced it will make any difference. I went thru the same with my FJC, spacers wound up on the shelf after rubbing and no percievable difference on the road or trail.
Bottom line is that you are planning on adding some significant mass to the highest point of leverage on your vehicle. That requires adjustment to driving techniques and vehicle performance expectations. When I ran my RTT on my FJC, negotiating the same trails became a new challenge, driving the same highways made me rethink what my goals for the rig were and made the necessary adjustments...