Just finished reading this 7 book series and I have to say, I rather enjoyed it.  It certainly helped explain a lot of what goes on in Duelist. I'd read the first 8 volumes in Duelist 2 years ago or so, and realized that there was some serious backstory missing. So after investigating, I realized that there were 3 series of Yugioh and not just 1.

So my journey has begun :-) I've been playing the cardgame for about 9 months now and I almost think that is a drawback to enjoying the manga cause the real game is so much more complex and none of this "Well, I'll twirl my butt and make my monster 3 times bigger" "Oh!? Well, I'll twirl my left foot clockwise and make the sky turn purple, giving my creature a powerup that nobody has EVER heard of so I'll WIN!" type of silliness.

I am looking forward to the Duelist series after reading this though. I like the drawing style a lot too...