4x4parts.com sells ones that are stiffer and last longer.
Most of them are made by Sway A Way (SAW), and private labelled for resale under various other names, so, generally, you get the same actual bars everywhere.
BTW - While they DO break from fatigue cracks, etc, from time to time, its much more common for the splines to strip the anchor's splines and let the bar spin, making a loud gunshot-like bang as it lets go.
Either way look at the LCA and cross member anchors and their splines to make sure they are not stripped. If they are, you need them too.