Dopogue, I have no idea why you would say that inverted and uninverted polarities are identical. On many recordings that just is not true. If by saying that "most speakers are not polarity-coherent" you mean that one driver is inverted, I would say that buyers should avoid them.
Mind you I am not saying that matching the polarity of the recording, if there is one, is a major contribution to the quality of sound, but it certainly adds to that quality.