There has been a debate when it comes to zombies, which is better fast or slow?
For me I'm torn between the two, while I side more with the slow zombies. But every now and then who doesn't like a fast zombie?
The genre was started with slow moving zombies, which makes sense because zombies are reanimated corpses. They don't have the muscles needed to move at a high rate of speed due to decomposition. While they are easy to get away from (unless there is a huge horde of them), there is always the fear that eventually they will catch up with you and usually more will have joined in the hunt along the way. This leads to a horde that could be in the hundreds, spelling doom for you and whoever is with you. Not to mention what are you running into by running away from a zombie problem?
Fast zombies are in fact just that: fast. So fast that they could probably out run an Olympic sprinter. This means without transportation, you have to bunker down and try to defend a location. Problem with that is, just like slow zombies, that zombies will swarm and create hordes making impossible to fight them off. If you can survive the zombies, another mounting problem is supplies and sanitation.
Everybody poops and pees. So you're stuck and I doubt the water department is still up and running. The only solution is to be able to dump it outside. The supplies are limited and will run out. Stuck here and surrounded means that is all there is to live. Even if you could sneak out to scavenge, these super fast zombies would have you before you could yell help.
Both have their own element of horror, it really just depends on what you like and which you find scarier.