As an owner of the Zeros, I have to say that the red is WAY cooler.

In all seriousness however, I can see little difference between the models myself, even under direct comparison. I believe some of the difference lies in the hub bodies; the internals of the Zero and the One are the same, according to the schematic, but the hub bodies themselves are different. Of course, this may simply reflect different finishes and labeling, but it's a good bet, along with rim cross-section differences.