IMHO... I would buy new.. especially when you can get a new one with WD and Sway Control with a ball installed for only about $50.00 more than what you are spending now.
Here is a link for ya to take a peek at.
EAZ-Lift And you can choose the weight rating you need for your trailer application.
As far as the sway control is concerned... if the WD hitch is set up properly, the TV is set up properly, and the trailer is set up properly then 99.99% of the time you will not need it.
However, for that .01% of the time that you need it you will be glad you have it. You can't predict wind gusts, passing vehicles, and evasive maneuvers. Plus it will make the tow a little more comfortable.
Thanks!
Jeremiah