Like an arthouse movie playing a limited engagement, “Stage” has reached only select audiences — in Ohio, Virginia, Wisconsin, and a few other states. But if there were an ­Oscar for political commercials, advertising analysts said, the anti-Romney ad featuring a worker laid off by Bain Capital would be a serious contender.

The 60-second commercial that first aired in June topped a survey by Ace Metrix, a firm that studies advertising effectiveness and deemed the spot this election cycle’s top ad, quite a distinction, considering the campaigns and their supporters have spent $733 million and counting on a never-ending barrage of commercials.