The way I look at it if it taste better than the other varieties of eggs, then it's definitely worth paying the higher cost however if one is buying the eggs for the omega 3's, look elsewhere.
One large omega-3 enriched egg usually contains .4 grams of omega-3 and 1.6 grams of monounsaturated fats, while its store counterpart has .04 grams of omega-3 and 2 grams of monounsaturated fats. The hens are fed a special diet of ground flaxeed, which provides our body with Alpha Linolenic Acid (ALA). Our body tries to convert ALA to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (which is more readily used by the body), however it's highly inefficient. That's why is always best to get omega 3's from fish, which is a direct source of EPA and DHA and no conversion is involved.
Sorry for the spiel but I continually have this conversation with my mom, who buys egglands best for the omega-3's.
Erik