My experience is that the most appealing story badly presented will outsell the dullest story displayed dynamically. In this respect, content is indeed king. I’m not sure if these ratios hold for service magazines, but for business or news magazines, the best cover subject will outsell your worst by a factor of 4-5—even more if you have the flexibility to increase draw when you know for sure you have a once-in-a-decade winner. Variations of two to one are not uncommon in a typical year. In this regard, the biggest mistake editors make is putting the most important, rather than the most appealing, stories on their covers.
-- former Maclean's and Canadian Business publisher Paul Jones, as part of an interesting Q & A with circulation consultant Scott Bullock on his CoversSell.com blog.