I started with a Hensley, then moved to Reese dual cam after breaking the Hensley towing my Weekend Warrior. Towed just as good with the Dual Cam. I never once missed the Hensley. For all the other trailers I tow, including car haulers up to 12,000 pounds, I don't use any sway control.
My thoughts on friction-based systems, including the Equalizer: The force that resists sway will also resist other motions. For example, say you got on the throttle too hard in slippery weather and you back end kicks out towards the ditch. With a non-friction hitch, you just let off the throttle and everything straightens out. With a friction hitch, you may have a harder time straightening things out.