First, see the link in my signature, the section on sway control. Below is a recent post I made about WDHs.
There are 4 types of sway and/or weight distribution, with the sway bar being the lowest level. It doesn't do any WD and only attempts to stop sway after it has started. However, I always recommend the next level for pods, a full WDH that includes sway control. The lowest level here is a combined WD with friction control, like the Equalizer or E2. Above that is the cam type like the Reese Dual Cam, which actively prevents sway before it starts. The highest level is the Hensley Arrow which actually guarantees no sway period.