Doggystyle was better. There's really no argument. BUT I will say that Doggfather is very underrated and is a great album. It's just that it was the follow up to such a classic and lacking Dre on the production made it get overlooked. There's plenty of bangers on there for sure though.
I don't know if you'll have any luck getting a copy since it is such a rare and hard-to-find album. I'm guessing all of the stores and online stores are sold out of this rarity.