I've had my UM3X's for about a month now. I am still adjusting to the closer presentation since I have been listening exclusively to speakers for many years now. But the high's don't fatigue my ears like the SR-60's do, which is a big plus. They're also good for playing 3D games too since they isolate so well and are comfortable for hours on end.
I do feel they NEED a good source though. I am newer to this hobby but I discern a substantial difference between my 1st-gen iPhone and the line-out on my Xonar STX, for example. I don't really like using the iPhone, while the STX is quite enjoyable. I have been researching some better portable sources now, since none of my Apple sources "do it" for me anymore.
I let a friend try them out. He was skeptical why I would spend over $300 on them. He's used to Skullcandy's and other cheap headphones, which made his reaction understandable. We had a smoke and then I let him try them out. He was flat out AMAZED at how good the music coming out of his Nano sounded. He kept changing tracks with a big smile on his face, saying "oh my gosh, oh my gosh" over and over. When he (finally) let me have them back, the first words out of his mouth were "I'm saving up for those." Case closed!