I didn't vote, but....
I have the SM3's and have had the fortunate opportunity to have heard the UM3X's before.
Without going into details.... I'd say that the SM3's are better, I'm not saying that the UM3X's are no good, they're great, but the SM3's to me, just does better.
But of course, this is just my opinion.
I think you will need to specify in which areas is the SM3 better than UM3X for you. For me, I didn't find the SM3 to be better at everything, namely instrument separation, representation of cymbal and bass impact.