Sprouts is like the love child of Whole Foods and Trader Joe's. It offers more of the all-around grocery store like Whole Foods, but offers prices similar to Trader Joe's, and exhibits the healthy, all-natural, organic products that both Whole Foods and Trader Joe's capitalize on.
Sprouts has recently become my primary grocery store mainly because of the produce section. The fruits, veggies, and herbs Sprouts offers are always fresh, in great shape, and usually cost less than other stores. I'm also in love with the quinoa with dried cranberries their deli has ready for me (well, anyone). Sprouts also has a meat counter with seafood and a lovely bulk selection.
Bottom line: cheaper than Whole Foods, more selection than Trader Joe's.