Edit: As bm1362 says below they've since regained it, but it's still not best in class. From the article: "The Model 3 is now the fifth most reliable out of 12 luxury compact cars in CR’s ratings of predicted new-car reliability, just below the Audi A3 and above the Acura TLX and Mercedes-Benz C-Class. The Model S is the second-most reliable out of four ultra-luxury cars, just below the Genesis G90. "
Edit: As bm1362 says below they've since regained it, but it's still not best in class. From the article: "The Model 3 is now the fifth most reliable out of 12 luxury compact cars in CR’s ratings of predicted new-car reliability, just below the Audi A3 and above the Acura TLX and Mercedes-Benz C-Class. The Model S is the second-most reliable out of four ultra-luxury cars, just below the Genesis G90. "