The compound of the rubber is different, but a lot of people developed an EL prep out of marketing, and some because they had a combination that actually worked, but was easier to market it as it's own prep.
There are people that claim a lot of things, that they used this prep, and that prep, and you don't need these fancy gimmick preps, and some swear by them. Chances are those EL preps contain a few of the same chemicals we all use on the rest of our tires. There's only so many chemicals out there that work. It's more about find someone in your area that has good results and good customer service. If you're going to run EL a lot, learn them and the prep you choose. And, if you're struggling go to the person that makes the prep and talk to them and actually use their advice.