Stacking health is most important when building items on her. Warmogs, Sunfire.
Depending on team compositions, you can focus secondarily on CDR or resistances.
She's certainly viable, and can do lots of damage by just building health and a Liandry's. Her AOE stun is ridiculous. She's certainly worth playing. --- http://i.imgur.com/6AzX0.gif http://i.imgur.com/x7ji9.jpg http://i.imgur.com/sA2IS.gif