I believe one magazine showed the Camaro out pacing the Mustang, but everything else has shown the Mustang as a better handling car, and even draws major comparisons to the BMW M3.
I think the same review youre talking about was the one that was posted on here. Which I believe was against a base model Mustang GT that lacked its brembo brake package.
Keep in mind, Ford did have a supply issue with the Mustang GT when it first came out, they did not have enough wheels, so sales were slightly short on it.
If you look at current trends, Ford should be outselling the Camaro by about 1.5:1.