By themselves, miracle berries do not taste like much. The reason to eat them is that they contain a chemical called miraculin that binds to the sweet taste receptors on your tongue, changing their shape and making them respond to sour and acidic foods.
The upshot of this effect is that some things you eat taste spectacularly different. Straight Tabasco sauce tastes like donut glaze. Guinness tastes like a chocolate malt. Goat cheese tastes like cheesecake. After about an hour of craziness, your taste buds go back to normal, no harm done.
