the difference is the configuration of the wires on the terminated ends. The green wires and orange wires are just switched in their positions. For normal use it doesn't matter which you use.
At work, we use B standard. It doesn't matter what you use, but whatever you use - make it the standard.
It's nice knowing whatever cat5e end I put on an ethernet cable that I know what pattern I am to be using right off the bat. If you use A standard here, B standard there, etc, things will eventually cross over, and you'll find yourself in that situation where you have 1 shot to put an end on right and you realized you just made an A/B cable and have no more ends. Now that's a recipe for a good day!