I will compare them both:
Can be given an Assualt vest to make all damage 50% less. Has access to Cotton Guard, but loses assault vest if used. 472 base stat without Assualt vest or Fur coat added in. Has an ok movepool, but no recover (useful move for walls).
Can be given eviolite, which gives the effects of both assault vest and fur coat. Doesn't get Cotton Guard, but does have access to Reecover. Has 515 base stat without eviolite added in. Has a better movepool than furfrou.
So in my opinion I would do Porygon2. The access to recover is what really makes it better. Hope this helps!