I have owned all three, and my order of preferences is UM3x=W3>>>W4
The W4 was a disappointment to me. A nice, non-fatiguing sound but too little bass and overall quite boring.
I loved my UM3x (and still regret selling them to fund the W4s). They have amazing separation, excellent mids, and punchy bass.
The W3 are what I have now, and though they are a bit less composed than the UM3x, they are a lot more "fun" than the W4 and I enjoy them quite a bit.
If you listen to lots of rock, the W3 are much more suited than the W4 I think! Plus they are a good bit cheaper! I have noticed their slightly harsher treble a bit,
but it really isn't a problem IMHO, and is worth the trade-off for their more dynamic sound.