George wrote:

What do you have against two pieces of MDF tacked together?

MDF doesn't really have much strength. You'd have to support it better
than you would with solid wood or plywood, otherwise it'll sag or bounce.

I have a wall-mounted particleboard workbench with continuous support
along both long edges as well as cross-members every few feet. If I
pound on it with a hammer everything on it rattles and bounces.

Chris