A well-made and covered balsa rib wing will probably be the lightest and most efficient but also the most fragile of the three.
You may well warp your wing while building it, storing it or leaving it out in the sun for too long while depending on your covering material it might be pierced by as little as dried up grass stalks while landing.
Somebody tell me again why I just ordered parts for one...?
A glass-laminated foam core wing will also be pretty slippery and efficient, but the core will make it heavier and you will need specialized equipment to cut the core. laminating can be smelly, messy and altogether unpleasant, too.
They're also pretty much imperviouss to most storage and transport accidents.
You can also balsa wrap a foam core but the wood in turn will need protection by either paint or covering film.
Foamboard wings are cheap and cheerful, light and sturdy. They might not be the most efficient, especially with voids and bumps created by the foldover techniques used by most FliteTest planes. Short of getting slammed in the car door, being stepped on or folded in half by g-forces their only enemy is moisture and maybe too much heat, which will soften the glue joints.
So you basically have to choose 2 out of these three: cheap, sturdy and efficient.
And yes, a solid crash will do any of the competitors in...