I think they have a lot of store brand and different frozen prepared food like orange chicken, seafood dishes and such, many from around the world, along with frozen vegetables. And fewer national brands of dairy products.
They don't have any/many national brands of canned veggies or sauces in jars, etc., so it's a great place for people who like to try new things. Lots of snacks, crackers, beauty products that are not main-stream, and candies, and lots of wine.
I'd say if you like Aldi's you will like TJ's. If you are someone who buys pretty much the same things and can shop from your usual products list, I doubt you'll like it.
As another poster pointed out their meats are pre-packaged, and some from other countries, which is not my favorite thing.