I only use wire.
One of the main reasons is rig tuning flexibility, and the fact that my mast can move up and down with a jack I have at the base that allows me to increase shroud tension on the go, without the need to stop. I have all scaled down and know what tension does each centimeter of mast movement correspond. This would be harder to do with all rod. (unless its Carbon fiber).
In my case we didn't know where the whole thing would end up, and tuning intially called for wire, and i have a quite thick rod, to allow me to sail ion harder winds..
With rod, its ok once you know where you want things, which was not my case, and having to re-rig was not worth it.
Here's my wire rigging.