The ESSB is awesome. I have 3 SSB TX bandwidth settings, and I have alter the high setting to get 3.7KHz wide. That's as wide as it would go. It's not exactly ESSB, but I am told it has a nice effect by adding a little more bass and treble to my audio.
I have a nice wide range center channel surround speaker designed for home theater systems. The center channel speaker is designed specifically for dialog and voice. But they are the perfect radio speaker, and they show off the extra bass and treble tones of radio audio very well. I have heard many of the ESSB hams and they sound almost as good as commercial AM broadcasters.
In addition to using wider TX filters, they use studio broadcast mics like my Heil PR-30 (See my avatar), and they connect tham via the ACC socket on the back of the radio. Using the ACC socket connection bypasses the audio filters in the mic amp and allows a wider frequency response of your audio. The audio is a bit cleaner and less compressed sounding.
The wide AM guys are also amazing. Many use up to 10 or 15KHz wide audio and sound as good or better than any high quality AM commercial broadcaster. Almost a wide FM quality. I used to listen to 5 guys who did this on the 75 meter AM window. I used to drool and wish I sounded half that good on AM.
The only problem with ESSB is that the wider useage of the frequency spectrum would bleed much farther than the typical 2.4 to 2.9KHz SSB emissions in each direction from center channel. You could tune 3 or 4 kc up or down and still barely hear them squeaking. But the audio quality is nothing short of awesome.