There are tradeoffs for both Zirconia and Porcelain. Zirconia is regarded as significantly more durable than porcelain; it is much less likely to chip or fracture and it handles the everyday stresses of eating as well.
It’s a matter of opinion but some patients think that porcelain has a somewhat more natural look. Both are white and both look extremely similar to a patient’s original teeth. It’s a choice that is ultimately decided on an individual basis between the dentist and the patient.