I found a big difference in smell between the two. I didn't like the Concentrée all that much. It has a weird thick, cloying quality that I don't care for. After trying the Concentrée first and disliking it, I discovered the original EdC and was surpised that I really liked it. I bought a bottle. I get decent longevity out of it, but sometimes I do refresh. Often, fragrances with iris/violet leaf notes cause the wearer to have olfactive fatigue rather quickly-- thinking that the scent has died out on their skin.
I prefer the original by a mile.