There is no "one" form of garlic that's "better"; they all have their uses.
Fresh whole cloves,
all have different flavors profiles and properties (intensity, etc.), and multiply the effects by raw, cooked and how long cooked.
Similarly dried garlic tastes and behaves differently than fresh, and ground and granulated are different.
My point again is, it all depends on what you want to accomplish. Ground in a rub, and granulated on a grilled steak, for instance. Do you want the flavor to blend into the meat, or do you want that bit of granulated garlic mouth feel and intensity on the outside of the steak?
Biggest problem, I admit, is resisting the "great deal" of buying ground garlic at Sam's by the lb. If you're not going to use that much in a few months, you're actually wasting your money, either by throwing away, or worse, using powder that has lost it's potency.