Used, if you can inspect it. A first board gets dinged, dragged and probably sold within a year, and a used board absorbs all three. The catalog lists 2,474 used boards right now at a median of $550.
What to check on a used board
Weight. Lift it. A waterlogged board is noticeably heavy for its size and often yellow around old repairs. Walk away.
Dings. Press around the nose, tail and rails. Soft spots and cracks that have not been sealed let water in. Sealed repairs are fine; open ones are a job.
Delamination. Bubbles or a hollow sound under the deck where the glass has lifted from the foam. Common on old epoxy boards left in the sun. Hard to fix properly.
Fin boxes. Wiggle the fins. Loose or cracked boxes are a real repair.
Creases. A line across the deck or bottom means the board has buckled. It will snap.
Stringer and tail. Pressure dents on the deck are cosmetic; a crushed tail is not.
When new makes sense
Soft-tops: new is cheap enough that used rarely saves much, and old foam absorbs water. Longboards and midlengths: used is where the value is, since they hold up and the shapes do not date. A new board also comes with a stock size chart and liters printed on it, which takes the guesswork out of matching the calculator number.