I gotta say, I was hoping for a subrace that was more variable in appearance. I never really played much Planescape, but I like the idea of perhaps a more chaotic demonic rather than lawful devil breed, one that may or may not have a tail, etc. but still bears some obvious signs of infernal influence.
Of course this doesn't include the presumed subrace options, but the general description there seems to say all tieflings share the same baseline template.