Strolling around CGs, the most popular WDH by far is a simple round bar type and no sway control, regardless of TT length. Second most popular looks to be an equal-i-zer. Least popular are the Reese dual cam and Hensely/ProPride. 'Course, survey says nothing...
We have the Reese dual cam on a 29' TT and love it. No sway, ever. In the 5 years since I installed our dual cam, I've only ever seen 3 at most in CGs. The Reese DC takes more effort and know-how to install and adjust though and has some unique issues that may need to be dealt with sometimes. Worth the effort IMO.
But remember, it's more than just the WDH you choose and how you set it up that affects sway.