Baking meatballs at 400°F is generally better than baking them at 350°F. The higher temperature helps the meatballs develop a nicely browned and slightly crispy exterior, which adds a lot of flavour and improves their texture. Baking at 400°F also reduces the cooking time, meaning the meatballs spend less time in the oven and are less likely to dry out. At 350°F, while the meatballs will still cook through, they might not brown as well and could end up with a softer texture. Therefore, for a perfect balance of a juicy interior and a flavourful, caramelized exterior, baking meatballs at 400°F is typically the preferred choice.