My father often quotes an old union organizer he knew well, who used to say that he’d never organized a union yet, the company did all the work for him before he got there. My father is pretty much a militant union guy. My father-in-law works for a company that is rabidly anti-union, but carries that policy out by being proactive with its work force.
Dave Johnson at See the Forest points out a rather successful company that succeeds marvelously with a union in place in a highly competitive industry–Southwest Airlines.
Regardless of whether a company is unionized or not, the key is to promote a collaborative relationship with employees.