Trader Joe's has some products that I will only buy from them (gnocchi, flatbread mushroom pizza, thai dumplings). They do have a decent selection of items that can satisfy all appetites. However, the store is rather small and the items rather limited. It is good for picking up a couple of things, but every time i went there with an intention of getting groceries, i would lack something and have to go somewhere else to get it.
They have very friendly staff who are also very knowledgeable about their products. I would suggest reading the labels though, as some of the products are not as healthy as they are marketed to be.
All in all, I am happy with the place, but wouldn't do the bulk of my grocery shopping there.
Cons: Limited selection, Not close to metro, Not entirely health-oriented