Without taking anything into consideration, I was going to agree with somewhat defensive, since I'm a fan of defensive guys (Shuckle is my hero, currently). But after really thinking about the typing, I can't agree with going defensive. Weakness to Ice, Ground, AND Dragon mean that a great deal of things are going be able to hit hard.
Alternatively, since it gets STAB on Electric and Dragon, both good attacking types, I'd say that opting for a more offensive spread would be a good idea. And it could certainly work awesomely with Adaptability, which just feels wasted on Porygon-Z.
So somewhat offensive.