Depends...

On the one hand, most people know the default levels by now.

On the other...

I think that if the levels were specially designed to be completely even, and if there were no secrets or hidden elements, then these levels would be the best duel levels.

Something open, easily navigated, and a complete mirror of itself, in design and powerups. I theorize that this would be the ideal dueling condition, creating an arena like battleground.

Of course, this is just a theory.

~Buster