AA has more porting, the porting is equally distributed, and runs from the threads to the tip.
The freak front has less porting and it is over a shorter distance.
The freak jr front has a few lines of porting for most of the front with a couple more lines added a couple inches from the tip.
The only difference you'll find beyond style MIGHT be a slight difference in sound signature (more porting=more quiet) and efficiency (porting too early in the barrel releases the air before it has finished accelerating the ball). Any difference would be negligible, so get what looks good.
Also, check out the deadlywinds Fibur. takes freak inserts, made of carbon fiber, super awesome.