There are many varieties of creamcheese available. Look for young cheeses with a far-off use-by date. Cream cheeses are designed to be eaten as fresh as possible. Eat 3-4 days after opening.
Plus, the longer they sit, or things sit in them, the better they usually taste. Also, don't overwork the pimento cheese; it should have texture — not be a flavored creamcheese. One more thing: ...