You can tell they are from the same blender just as you can tell that about the various Viaje cigars (and can tell that those two brands have similarities ...).
The Epernay is Dion's best work, imvho. It's elegant and sophisticated. Lighter on the palate than his original line or Cruzado, it's creamy and sweet with that dark, rich tobacco still coming through. Not nearly as spicy or strong as the regular line. I find the Epernay to be closer to a Cuban cigar than many other sticks that claim to be "cubanesque."
I love the Epernay, if pressed I'd probably say it's my favorite of Dion's stuff. But I smoke the regular line more often because i've gravitated towards more full-bodied cigars this past year.