I live in Aldi's motherland and even if I could easily afford to buy groceries in other stores from major brands I usually go to Aldi first, buying the 10% they do not sell later somewhere else. Why? Because I blindly trust them. What they sell is usually good quality with a good taste (I even do not look at the prices). The juices they sell: perfect. The fruits they sell: mostly sweet (there is a fruit quality problem in Germany, as the country usually only gets second grade fruits because of the low prices eveywhere). Milk, joghurt, cheese: best quality. And I can actually remember where stuff is! So shopping is fast. This is in stark contrast to most other retailers who try to trick you into buying more by hiding stuff in unexpected places. Many years ago, someone told me something from behind the scene at Aldi. She was working for a producer of toilet paper and similar. She said: in contrast to other clients, we are not allowed to produce one lot without some people from Aldi being present. Before they produced for them, they had to call Aldi so they could have engineers at the factory to oversee everything that was done. She said no other customer did this.
This really reinforced my trust in their Quality.