A lot depends on whether you only like top brands with which you are familiar.
Aldi and Lidl market many of the top brands in Germany, and the quality is very good and extremely comparable in most cases with the goods to which you may be more accustomed. I would recommend you try something once, if it's not a lot of money. If you don't like it, at least you know. We have only rarely been disappointed, and that was a matter of personal preference rather than poor quality. (The only thing to watch out for is popular British brands on the shelves alongside theirs - there may be a special deal on them, but often they are not cheaper here!)
We have found their supermarkets not in the town centre, but not too far away, in a well-populated residential area - not on the outskirts of town like the biggest supermarkets.
Currently, in the centre of town, we have a fresh fruit and veg. shop which markets local produce; and a fresh fish shop where they go out in a family-owned boat and catch their own produce three times a week. We are trying to support both, in a modest way, as we want them to keep going!