I subscribed in the late 1970s.
I thought it was brilliantly written, and I learned more about Classical Liberalism, European history, business, and technology, than I learned in the previous twenty years.
For me, The Economist started falling apart in the mid 1990s, at almost the same moment that the editorial page of the Wall Street Journal started claiming that Hispanics were natural Conservatives, aggressively endorsed mass Amnesty, and aggressively endorsed Open Borders for immigrant labor.
1995-2000 was a political horror movie for Main Stream Conservative publications.
The Economist, the Editorial Page of the WSJ, and National Review, all moved sharply to the Center and the Center-Left.