I'll just describe what I like about my grail pin Theatre of Magic
I like the fact that starting the <Gob>Illusions</Gob> is a simple straightforward process. The auto magna save keeps the noob from losing too fast and helps build the interest.
I think the fact that you don't actually have to complete the illusions once they are started is a plus for newer players as it allows you to complete the modes with a lower score.
As the skills increase you start completing the Illusions rather than just obtaining them. This yields higher scores and offers some nice animations.
Next you start learning tricks to advance the clock like hitting the captive ball when plunging after a lock. The satisfaction gained after advancing the clock and having the deflection hit the trunk to complete the locks and start multiball is exceptional.
In a nutshell I love that you can play this game with a minor level of skill and you can hone your skills on the same machine.