Not back to back, but I've heard the 2s and 3s on a few systems and always came away with a similar feeling that they were just too neutral for me. They're obviously great cans, some of the best in the world and there's no doubting that, but just a bit too "HiFi" and emphasizing detail and accuracy for my ear taste. These new ones sound a bit more fun to my ears, retaining the really impressive cohesiveness despite also having very distinctive separation, the combination of which is one of the defining characteristics of the LCDs IMO, but they're just a bit more fun overall, the bass is a bit fuller with greater impact and body, while retaining impressive speed and accuracy, which I know not everyone enjoys but I sure do. I also feel that the midrange is more full and forward; it has that really impressive raw, live feeling that you get more often from headphones from Shure, whereas I have always found the LCDs to be a bit more clinical and tonally balanced in this regard. I would say the EL-8 sound is more beautiful and immersive, whereas the LCDs sound is still the king of technical perfection.
The true lovers of ultimate detail and perfect technicality among us will likely still opt for the LCDs, but the EL-8s are a cheaper, more "fun" alternative that suits me better for casual listening, and may appeal to a wider range of people than the LCDs. It's still an intensely detailed, highly accurate headphone, but I'd say it's a slightly more fun take on accuracy. Don't get me wrong, it's still very obviously an Audeze headphone and they have by no means stopped so low as to appeal to mass market tastes (thank god), but with the LE-8 they seem interested in capturing the attention of those of us more interested in casual listening and those who like the "feel" of good audio quality rather than those who obsess over the tiniest imperfections in tonal balance and perfect accuracy; the latter are who the LCD series have been designed for.
