We're very happy with the A/C here in Texas (though our car is white and has tinted windows, makes a big difference). I had a rental Corolla over the weekend that was charcoal gray with black interior and it was amazing how much hotter it got inside after sitting in the sun.

It does seem to make a bigger impact with the MPG compared to other cars. With the A/C off, it's easy to get 45-50 MPG bombing around the suburbs. But with it on it is strictly high 30s/very low 40s for us.