These "zombies" aren't completely dead; they have beating hearts but minimal brain function. They are primitive animals with no humanity left in them, only an aggressive mindset and the craving for human flesh. They are slow moving, their fastest speed akin to walking, but they swarm quickly to a target. Their overwhelming numbers is what kills most of the survivors. They have a good sense of smell, at least in close distance, which is their best sense. Their eye-sight is fairly good, but if you stop moving (at a far enough distance not to be smelled, or if you mask your sent with coagulated non-infected blood) you can go undetected. As for hearing, the zombies are all but deaf, so they won't be attracted to gunfire or shouts. It is still best to keep still and quiet if zombies are in the area, because the closer the get, the closer they are to smelling you.
Since they aren't dead, they have some good strength on their side. Some zombies can even climb, but not very well, since the muscles in their bodies decompose at a phenomenally quick rate. It's true that these zombies don't last very long, since the rabies-like virus destroys the brain within 5-10 days, but their ability to infect others means that however many you kill, they can infect twice as many.
The best ways to kill these "zombies" is to:
Shoot them in the brain; a tried-and-true method with no side effect (minus running low on ammo, which is why medium-range secondary weapons [baseball bats, machetes, swords, etc] are vital) to the survivors. You can also try hacking off limbs, like legs and arms, so they cannot follow. That however has the downside of needing to be close, meaning one risks infection. One could also try incinerating them, since they still are partially alive, but that brings up the downside that if you don't burn them enough they might still come at you before it kills them.