Yes, it's really fun to play with because you get to see some truly strange stuff.
The disc is from Aerobee, the ones that make the flying rings and the Arrow putter (which I like)
The only people that I've spoken to that like it throw distance thumbers with it.
A thumber is an overhand throw with your thumb on the inside of the disc. The Epic has a unique flight on a thumber which is how it gets more distance. Unfortunately, it loses the accuracy of other thumbers. I'll start with the flight of a regular thumber from a right handed player's perspective.
The disc is released almost verticle with the bottom of the disc facing left. Shortly after the release, the orientation of the disc starts turning clockwise until the disc is flying upside down. Depending on how hard the disc is thrown, angles and snap, it either maintains this upside down position or the orientation revearses to counter clockwise and it hits the ground on its edge with a backwards spin making it stop fairly accurately.
The difference with an Epic is that in it's clocwise turn, it will go past upside down and keep turning until it's right-side up, gliding at a higher altitude which is why it get's so much distance. The problem is that it rarely stops turning at flat and is slightly tilted either left or right, so the players I've seen get huge distance with an Epic, also have some pretty serious control issues with this shot.
In answer to your question over the usefullness, I think there are better discs out there. You can throw a controlled thumber with anything stable to overstable. I've had terrible results with throwing this disc backhand or sidearm.
Pred, Wraith, TeeBird, Eagle, Whippet, Cobra, Rhyno, Arrow