COMMENTS:
It depends on what you intend to do with the cow.

If you intend to fall from a great height and land on it then the styrafoam cow is your only man.

If you intend hold the cow up to your face and wrap the cow around your head then I'd stay clear of the PVC cow. PVC cows and head wrapping are poor friends.

If you intend to moisten both sides of your face and perhaps fashion a top hat out of your cow I'd stick with your regular blood and guts model.