I've tried frozen custard at many places (even the place down the hill that everyone thinks is good) and all I can say is that I'm glad that I live so close to Mr D's. We had been going to Sheridan's since it opened and were worried when it changed, but all of our favorite concretes taste identical to what we got when it was Sheridan's.
I've found that there are significant differences between various frozen custard shops. Some taste like ice-milk, I had one in Florida that was like eating frozen flavored water, but Mr D's is creamy, smooth, flavorful and if I could eat it everyday I would.