I've been in a couple of excellent stores. That's it- two. Ever.
One store, in Akron Ohio, had a decent selection and prices, but when I asked where the grain XX was, a clerk waved and said "All over". That's right, there were bins on the floor lined up down the rows, and around the long wall. Wellllll, I wanted five pounds of crystal 20L- I didn't want to search "All over"!
The other thing- three workers were in there. I went in with my dad. They all three asked my dad, "Can I help you?" which was nice. But I was totally ignored until I asked where the crystal 20L. I then asked to see a pH meter and when I had a question I got a shrug.
I really think I was ignored because of my gender, and I will never go back even though it was a pretty big store that advertises a lot. I bought nothing, not even a t-shirt.
I've gone into stores that have a nice owner but you have to order things because he doesn't have a high enough turnover to keep things in stock. That's fine if you only want to buy things he happens to have, but that is an issue. It would be hard to be "big enough" to stock most things without them outdating if your business didn't have high traffic.
The best store I've ever been in was Northern Brewer in Minneapolis. Midwest is the second store that was nearly as good. Competent employees, well laid out stores, a good variety of hops, malt, and yeast (all fresh and well packed and stored), and Midwest had frozen wine must in a huge walk in freezer.
Ironically, Northern Brewer and Midwest are only about 10 miles apart!