I general, Target has a wider selection of stuff (groceries included), but I find that they still lack compared to actual supermarkets. This is true even of the big, one 5 miles away from me that has a grocery section that is almost the size of a supermarket by itself.
Then again, such are the sacrifices of one-stop shopping. When you pick up motor oil, flat-screen TVs, a pair of pants, and a prescription all at teh same place, you really can’t expect them to do as good at groceries as a place that focuses more heavily on food.
As an alternative to Walmart, Target is awesome. I just find it odd to get groceries at either when there are better (and often cheaper) options available.