Trader Joe's is Aldi's chain, right? Do you have Aldi too in addition?
Aldi was formed by 2 brothers and then split after a disagreement about whether or not to stock alcohol. The reason I find it interesting is actually because Aldi isn't the first big brand formed by two German brothers to split into two (big, recognizable) brands. That honor would go to Adidas and Puma.
From my experience the US Aldi (which is part of an Aldi Sud) is a dimlit, bottom of the barrel discounter with a small selection of basics. Where Trader Joe's is a quirky "Hawaiian-themed" specialty grocer with a good selection of the unique-to-US products.