This isn't technically a review, but you can see how NARS's new Orgasm X blush builds and blends, and how it differs from original Orgasm blush. This goes on pretty soft and sheer for how intense it looks in the pan, but it definitely layers, and using a firmer, denser brush also deposits much more color than the soft Les Merveilleuses LADUREE one I used.
(Full products listed in the Youtube description box.)
To be 100% fair, it's not a huge difference between the two once they are on, and if you own the original and love it already, you probably won't need or want Orgasm X.