They are different for what you’re doing with them. If you’re eating them fresh, you probably want sweet cherry tomatoes or yellow bell tomatoes. If you want them for sandwiches, you might go with a beefsteak tomato because the shape and size make the slices perfect. If you’re canning them for sauce, you’ll want romas because they have less juice in them, meaning you can shave off a good chuck of time to get the sauce to thicken. And as others have said, the flavors are different as well.