Very similar. Tomatoes and tomatillos actually belong to the same botanical family. However, the main difference between these two is that tomatillos tend to have a more sour, acidic, and tangy flavour, whereas tomatoes are sweeter. In terms of texture, a tomatillo is more firm. It’s denser than a tomato and less watery, which might equal slightly higher cooking time. Tomatoes, on the other hand, are soft and quickly cooked.