I was talking to Egon and he said the only difference is that the cranks are different matterials. So ya, I dont know what else to say.
So he was saying that if you have a splined hub its more what cranks you have.
Isaac
There are old and new designs of the red and the yellow one.
The new design is with ISIS and the old is splined (yellow) and square (red)
So not only the colour is enough to figure out what Hub you have 
With implementing the ISIS Standard, the red hub becomes much better than before.
yes thats what I was thinking too I knew there were different ones. But ya.
When did the Yellow ISIS hubs come out? and why can’t I find them on UDC
The yellow hub is ISIS now also as you can read here
Maybe the single Hubs are still not on stock but they will be availiable for sure soon.