I had aluminum decking in the cockpit of my old 28, apparently put there by a former and smaller owner. Under my considerable body weight the stuff oilcanned alarmingly. It wasn't going to break, but it didn't feel sturdy.
I replaced it with 5/8" marine grade plywood with a topcoat of 6oz fiberglass set in WEST epoxy, leaving the texture of the glass cloth as sort of a nonskid pattern. It was OK and felt very sturdy. I have lost touch with the present owner but with sealed edges and all I suspect the plywood will last.
Wood is lighter and stiffer than most competing materials, which is its great advantage. At the time I had some star-board that I was going to use, but I realized that it would add a lot of weight aft where I didn't need it.
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida