One is currently out of fashion and the other is a golden boy. One is supposedly facing doom from the rise of Amazon and the other supposedly doesn’t face this threat. One trades at 11.6 price to earnings while the other trades at 30 price to earnings. One gives you 2.58 times more earnings off the bat while the other, well, gives you 2.58 times less earnings off the bat. Wal-Mart vs. Costco: which is the better asset to buy?