pretty sure the algorithm is the same (A*), the implementation of it is what is different. Read the wikipedia article about A* and then think about how to implement it, im sure you will come up with more then one way, but not every way thats possible is effective. Btw the two behaviours are too completely different, while the built in behaviour also moves the objects the easystar will only calculate the path. You should try both, far better then me explaining the difference.