I don't have time to compare it all, but some rough numbers from FY2011:
Costco: Revenues of 88.9 billion, earnings/share was $3.97
Target: Revenues of 69.8 billion, earnings/share was $4.28
So Costco MAKES more than Target in revenues. I didn't look for profit figures. But the bottom line is that Costco can probably afford to spend more on health care given that they have LESS employees and almost $20 billion dollars more in revenue. However, as an investor, Target looks like a better place to park my money as it has a higher EPS figure.
As an investor, Target looks like ****. Poor purchasing decisions, bloated "profits" that are mostly just tricky book work. Anyone can make it seem like they're making a profit. Long term however, we're going to sink faster than the Bismarck.