ROFL, it's so terrible unless you're willing to pay.
I tried it out before I joined Dueling Network, and holy-crap, it is TERRIBLE.
I mean, it's cool in that you can join teams and stuff, design your own duel-disk, etc. But the cards they give you to start-out with are LAAAAME
You have to buy cards to advance any, and thats an annoyance if i've ever seen one.
Beating the wanna-be COMS of our favorite duelist simply isn't enough
(Beat Jaden Yuki, Yugi, and other people many times, and no card reward!)
So yeah, screw that. It'd be awesome if you could obtain cards.