I've used both. Gore-Tex doesn't wear out. It looses the DWR finnish. Used as directed, that stuff works by replacing the DWR finnish on Gore-Tex garmits. Many of my backpacker/mountaineering friends use it.
I've used the stuff designed for boots as well. If the boot was built as a waterproof boot, and it did work while new, it will work. I haven't tested it on non waterproof boots, or approach shoes. On those it is reported to enhance water repellant features, but not turn the boot/shoe waterproof. Makes them easier to keep clean, etc.
It's big attribute is ease of use on a very wide variety of materials. If you need to waterproof a leather boot that wasn't built that way, I vote for wax. I have had good luck with it in that application. E
