I'd take THE POLISH HAMMER over Bynum, Varejao, Noah, Pekovic, Bogut, and possibly Lopez. Maybe Duncan for longevity, too.
Healthy Bynum, Bogut & Noah are all better than Gortat. I'll admit Lopez & Varejao were stretches to an extent.
Ok yeah if I'm building for the future I take Gortat over Duncan, but as far as they go right now, Duncan is better.