Eh, the description of it's venom is basically like any colony dwelling wasp. It is used for defense, hence it has pain inducing properties. Now I'm not saying it doesn't hurt, but if you've been stung by other paper wasps, bumble bees, honeybees, you know just about what it feels like to get stung by this guy. However, since this hornet is bigger, it has a bigger venom gland, so it injects more venom than it's smaller cousins, which will hurt more.
One thing to note about wasps and hornets is that solitary nesting females use their sting to subdue prey. It's a paralyzing shot rather than a enemy deterrant. The stings from solitary nesters (mud daubers, potter's wasps) have been reported as less painful than those of colony nesting wasps. It is believed that worker stings are for nest defense, and since paper wasps and hornets don't hunt prey, this stands to reason. The adult wasp feeds on nectar. They gather caterpillars and grubs, which are minced before returning to the nest, to feed the larvae. Paper wasps and hornets have powerful jaws that allow them to collect their quarry without the use of a sting.
Mud daubers, tarantula hawks, and other "spider wasps" are solitary nesters that prey on spiders, and they need the sting to subdue prey that is often as big as them. This sting also paralyzes the spider, but does not kill it, whose living body will serve as food for the larvae. The female lays an egg on the spider, backfills the nest hole, and the egg hatches onto it's living dinner.