Depends what you’re comparing. Gross economic force of two entities? Raw GDP; Quality of life? GDP-PPP/capita is better.

Private citizens don’t generally get to threaten governments by moving abroad to withold their taxes — and even when they do (I kinda am!) it’s so completely irrelevant it isn’t worth the government’s time to bother to check if it’s actually happening or just a loudmouth blowing off steam by saying they will.