I think the Jeppesen maps color in more areas than the others. Keep in mind it's potential turbulence, as opposed to guaranteed turbulence.
The truth of the matter is that this is still more of an art than a science, hence the disagreement between the maps. I like to look at them all to get the big picture. If they all show in the clear, then that's pretty easy to say, well, it's probably going to be smooth. If they all show colored in, then chances are good that it might be bumpy. If they disagree a lot, than we are somewhere in between.