In 1950, Remington figured out how to make a well-balanced, great-shooting, reliable and durable pump gun for half the price of other pumps like the Winchester Model 12.
In 1961, Mossberg figured out how to make a great pump gun for even less.
In 1964, the Model 12 went out of production, missed and still loved by many, but unable to compete with a gun like the Mossberg that sold for a fraction of its price and, while not a handcrafted work of art, worked just as well, shot well, and lasted.
The 500 and the 870 have pretty much killed off their competition since then, other than Browning's Japanese BPS and the recent Benelli Nova.
Yes, the 500 is good.
(I dig the new Ithaca 37's, but they occupy a whole different niche, as they push a grand in price.)