composites are great,i like "penske board",great product.only problem with composites,is the fact they will not hold a fastener - if you're gonna need to fasten anything to the deck,you're gonna need to thru bolt,and "sleevei"t.if that's not an option,you have a few ways to go:
first-remove the coring in the area where the fasteners are gonna go - fill that area with epoxy - mixed with adhesive fibers - i use and prefer west system epoxy-mixed with 403 adhesive fiber - after this is kicked,drill it and install your fasteners.
next option is to laminate a "block" of plywood,encapsulated in epoxy,mount the product to the block as needed.
composites are polyester based - meaning,they're brittle - the vibration,will cause the fibers to break,causing a loose fastener - 3m5200,or other products will not cure this problem...
big fan of composites !