I shop at Trader Joe's often because it's convenient. It's really close to where I live. The staff are great and always willing to help. The produce section is not the best. I find that I have to look over the bagged fruits closely to make sure that they're not going bad or not growing mold.
I think I think Trader Joe's is great for dried fruits and nuts, cheeses, yogurt, baking items, and snacks. Most everything else is premade, which I typically don't buy. So, If you don't like to cook and rather pick up something to throw in the microwave, this is your place.