Ok, So I have driven both, but own a 2012 5.0 non r-spec. White Satin Pearl w/ Tan Interior. I definitely feel the additional 96hp. In my personal opinion though, I would not opt for the r-spec as I am not too fond of the rougher ride from the 19" wheels and stiffer suspension. I also don't like the fact that the r-spec doesn't have many color options or tan interior option and not too fond of smoked out headlights. Not to say the r-spec isn't a great vehicle, I just opt for a more luxury ride. To give an idea of price, I just bought the 2012 5.0 from CarMax with 44k miles for $22,998. Got a 150k or 5 years warranty for $2250. no deductible.
I agree on a few things. I myself don't care for the sunroof, harsher ride and the smoked headlights. I do however welcome the added HP and having every option available to me and also like how the wheels stand out on the black car but I won't kid myself I would have highly preferred a White with Cashmere interior.