I have towed with friction sway control and with a Hensley Hitch. The Hensley Hitch does not allow sway at all. It is a mechanical 4 bar problem that allows the TV to articulate (turn) but will not mechanically allow the TT to initiate a turn. For example if you had the TT hooked up to the TV while on clear ice and you used a tractor to push on the rear of the TT you would in fact move the front tires of the TV in the opposite direction. However if you pushed on the front of the TV it would allow the hitch to articulate. This is especially good in slippery situations where you could not use friction based sway control. The Hensley Arrow also provides for WD as well. I can't recommend the Arrow enough for large TTs.
2004 Chevrolet Silverado 3500 LT with a 2004 Jayco JayFlight 29BHS
2014 Greyhawk 31FS with a 2007 Tahoe toad
2014 Thor Palazzo 33.3 with a 2007 Tahoe toad