Fiberglass. No contest. Unless, of course, cost is a concern! ;-) I have a hinged glass hood with integral six-pack scoop. Saves a lot of weight. You have to weaken the hood springs or remove them and use a prop rod though.
If you go with a hood, go AAR. One more piece of advice.. if possible, run the hood on the car for a year, THEN fill and block it out and paint it. The fiberglass will move around a bit, and if you don't do this, the bodywork won't be perfect anymore. Ask me how I know!