I doubt your Rampage out hooks the EPX on a heavy oil type shot. I'm guessing that you bowl on a walled up house shot and expect the EPX to be able to cover boards and have a huge backend. If that's what you expected, then your Pro Shop guy sold you the wrong ball.
I agree that it may not be worth the cost to some people, but to others it's worth every penny, especially when it suits your game and/or the conditions for which the ball is at its best.