I prefer the exterior of the current mustang...interior wise, they did a decent job of not letting it be a cliche Ford interior. It does however appear to have slight layout likeness to the current lineup; but quality wise - it looks much better in comparison. Unlike the current mustang's interior which looks like utter shit in all aspects (looks no more special then the Taurus I have)
The exterior didn't turn out nearly as bad as some of the photoshops I saw that made it look like it was crying/dying. However the new mustang seems like something that you'd have to learn to appreciate over time, rather then the (for me anyway) instant love of the camaro, inside and out.