CDDA
>Much better and more varied loot
>Better and more varied zombies. Runners, grabbers, exploders, dogs, juggernauts and many more.
>Mutants, evil fungi and aliens
>Can become mutant or cyborg
>More animals, including dogs and cats that can be tamed
>Zombies are tough and deadly, but they do not kill you instantly in one hit unlike Zomboid.
>Better character crustomisation.
>Medieval autism!!! Wear plate armor. Use medieval weapons like swords and maces. Ride a horse.

Project Zomboid
>Action gameplay!!!
>Faster gameplay.
>Much better immersion and sound design.
>Looks much better. Actual 3D envoirements greatly help the immersion.
>Handmade map instead of generic random generation.
>More intuitive and doesn't require reading 10 guides to learn about arcane things as focus, encumbrance, weariness, etc to play.
>Less menu navigation autism.
>Each item has a beautifully made 3D model.