We have a rear Henderson trac bar installed in back along with a heavy duty Roadmaster stabilizer bar. I can't say how great it is by itself because it was installed along with other upgrades. I can say that all together it worked great for a while, now replacing the tired 4 Koni-RV shocks with HD Bilsteins to get the rig back to 100%.
One thing I recall the installer of everything said... it was tricky to have both the rear HD stabilizer bar and rear trac bar together, maybe they share common mounting points, maybe an interference, not sure exactly what the challenge was. But they did resolve it.