If it's covered up by flavoring/sugar, then it may be hard to notice the difference. But if you just have vanilla or chocolate (with chips, nuts, etc.) then I think it's pretty easy to tell the difference.
In addition to some of the premium brands you mentioned, are there other even higher-end labels? And what is it, experientially, I should be looking for? What are the signs, good and bad, in the ingredients list of proper ice cream?
She is the founder of Jeni’s, which is probably the highest-end ice cream I’ve come across.
I look for the fewest ingredients. If I see preservatives or coloring I generally don't buy it. Haagen Daaz is one of the few national brands that is really good about that. Jeni's is really good IMO
I still felt a rush when I wrote those lines, and its been 5 years.