I own a big bottle of Reaction myself. Funny thing is that I don't really care for it much, but these so called "copies" usually smell better than Reaction to me. I guess that melon accord isn't really my thing.
I remember smelling reaction in store when it first came out. I really liked it but as a teen had very little money so I passed. I am surprised that I haven't revisited it since. If I remember, it wasn't anything too earth shattering just very much inline with everything else being released at the time. So if anything, it took cues from a lot of its predecessors.