These two foundational sauces are similar, and each varies cook by cook. But generally speaking, marinara has a thinner consistency with larger pieces of tomato running throughout, while pomodoro is smoother and thicker (due to longer cooking time or starting with strained tomatoes, which have already been cooked down a bit). Both are wonderful with pasta. Pomodoro is my go-to homemade tomato sauce in general because I love its richness and depth of flavor. I also use it for pizza, since it's nice and thick and not too liquid.