They are exactly the same, except the layout will be reversed, since they are on opposite sides of the ship. In other words, the bedroom will be to the left in 8522 and it will be to the right in 8078.
8522 is an adjoining room, which might make it possible to hear your neighbors, and you will lose a touch of wall space with the door.
I have always preferred the aft. The elevators aren't as crowded, which is perfect for getting to the dining rooms, it seems to be more quiet in the aft, and 8078 is much closer to the free drink station.
There may be a little more noise from the foot traffic above (Mickey's Pool) during the day, but at night it will be quiet...in 8078.