It has been widely shown that the dark side is the quick and easy path to power, and that many fall because the lure of that power is too great for them to resist.
Maybe the basic stuff acquired faster or to put it better, more effective with less training.
But Fanyen was right when he mentioned being free of restrictions, Ajunta Pall and his followers experimented with certain aspects of the force and the Jedi council didn't like it. So Pall went to war with the Jedi, a fight to be free to do what he wanted.
Don't forget that Pall was a Jedi Master who just used the force just like all others, but the council deemed him dark.
The force isn't evil, nor good. What we call light and dark is defined by a select few and is forever accepted as fact.
Maybe the new "Dawn of the Jedi" comics will give us more info about why some choose to be more dark?