Same as previous photo, but with additional luminance noise reduction (LR4 beta).
Next image in this gallery is the same photo with more luminance noise reduction.
I was able to retain considerably more detail in the highlights while increasing overall image contrast. In this test I was mainly focused on the improvements in LR4 beta's tonal adjustments in the basic panel. I didn't optimize other settings, like noise reduction (though, later I did confirm that increased luminance noise reduction can take care of the background noise in this image without compromising the improved highlight detail).
This is processed in LR4, for comparison with the same image processed in LR3.
This is processed with LR3, for comparison to the same image processed in LR4.