Just received my SM3s today... They're awesome
Just what I expected coming from the um3x, wanted something less aggressive(the veil they mention, which to me, sounds just natural tbh) and a larger sound-stage, which is not big, but the um3x is really claustrophobic.
The highs are right in the spot, as I am really sensitive to them. In the bass department, they're most likely the same really, perhaps little less quantity on the SM3.
Man, they sounded...