The graphics come close to the arcade, but you'll never have the exact gameplay unless you have all of the joysticks and buttons in all of the right spots. For Robotron as an example, you need 2 Joysticks to play it right. One allows you to shoot, while the other allows you to move in any direction as you're shooting. You can't do that well with just one "joystick", which is what you get with the Sega Gamepad.
That being said, this package of games could satisfy your craving for these old classics.