I could work with a bench like that just fine. My bench is one that would be classified as junk on this forum (and it sort of is, I guess). If I had a framed MDF bench, I doubt there's anything I generally do on it that would matter much. I'd glue size it first, though. I built a router table ala pat warner's description in one of his books (the versatile router or some such thing), and ran oak supports under it to keep it straight and flat, and it has stayed that for 8 years, but i've had to plane the MDF twice because it has unevenly absorbed ambient moisture. If it's sized, no problem.