A blush with a huge cult following and number of reviews almost at 2,500 on MUA, Nars' Orgasm has established itself as an all around crowd pleaser. A walk through any makeup store such as Sephora and you will notice that many other companies carry a suspiciously similar color.
I noticed some raves on E.L.F's version (named Glow). I bought mine online for 2.30 eur (it is sold in the US for $1). Who doesn't love a bargain right? Both are meant to impart a certain 'lit from within' quality on your skin, but E.L.F.'s may be more age-appropriate, considering that most of its fans' ages run a little lower.
The two blushes are no doubt equally gorgeous colors. However, I suspect that the copycat version will get used up very quickly. It's pigments are not pressed firmly enough so the slightest touch with a blush brush picks up a lot of pigment. Also, the blush being so soft leads to a high risk of the blush cracking (very messy if it cracks in a quad and gets onto the other colors). Not to mention, you get about a-third as much in the pan.
My Nars on the other hand, has endurance, class and dependability. It goes with me easily wherever I go and I know that its understated chic packaging will not embarrass me in public. At 10x the price, it's the least I could expect.