The original Video Essentials DVD is very good, although navigating the menus can be a little frustrating....the manner in which the disc is divided into chapters doesn't seem very intuitive. In addition to the test patterns and tones, it has an outstanding segment of both film-based and video-based images at the end, which is widely used by reviewers of display devices and scalers. And Joe Kane, the guy who developed Video Essentials, is one of the major gurus of the video field.
The AVIA disc is much easier to use, and has a much more comprehensive set of audio test tones, such as descending subwoofer signal from 200hz down to 20hz. However, it lacks the great test video sequence of VE.
If I was going to buy one disc, I think I'd start with AVIA, based on what I've seen. But I still haven't heard any reports of the new Digital Video Essentials, so I can't really make a fair comparison.