In my experience, they are pretty interchangeable. I think they are used in most BBQ rubs for color and filler/profit booster like most non-bbq rubs use too much salt. All of the paprika I've tried is very subtle and I really haven't noticed a difference in rubs because it's so subtle behind all of the other spices in them. I haven't tried any of the more expensive varieties though from specialty spice shops that offer the hot paprika, etc.Most of the rub recipes I've used, just call for paprika. And I always thought it was used just for color. So if a recipe just says paprika, its my option to use the Spanish or Hungarian ?
Yea those are some generic labeling. The Hungarian can be sweet or hot and the Spanish could be smoked or not.