Here is comparison test of videos recorded by Nokia Lumia 800 and Nokia Lumia 710. Both were shot at 720p video quality and as you can see, the video on the right is much better.
No doubt, the sound is indeed awesome in both the videos(as expected with Nokia handsets). Another common thing in both the videos is their stability. There is no blurriness or jelly wobbling that is seen in many new and upcoming smartphones.