I liked the Mustang when it first came out. Now that it's been on the market for a while, I'm kinda indifferent to it. The updated front end and tail lights are ok. But still not enough to make me want one.
I really want to like the Camaro. But it's so generic, and looks too similar to the new Dodge Challenger. But if I were to choose between the Mustang and the Camaro, I would get the Camaro. But the SS model. I just don't see the point in getting the RS.
Another reason to get the Camaro.. independent rear suspension. Better handling, and more fun to drive. Solid rear axle (like on the Mustang) is fine if you want to take your car to the drag strip on the weekends. But for daily driving, I think the independent suspension would be better.
But if you're buying a car more for style and not for performance, then either one is fine. Get the car that YOU really want. Because if you make the wrong choice, then you're going to dread getting in your car every morning.