I have a long standing history of hating IEMs, basically exhausting the entire Shure product line as well as a variety of Sonys, Beats, and others...all of which I found to be essentially trash. I stuck with a variety of beloved Sennheiser on-ear headphones until I came across the S4 from Klipsch. That humble IEM lead me to the Monster Turbine Pro Golds and my desire for better has lead me to purchase the UE 900.
While these are the best IEMs I have ever heard, I am still not convinced they're worth $320 more than the Klipsch or $150 more than the Monsters. Of course, the soundstage is infinitely wider and the mid-range much more buttery, but I am still struck at how weak the lower end in the UE 900 are. I am a Comply guy and I know I am getting a good seal and proper insertion depth, but I can only assume that I have a bad copy of this IEM? The bass is absolutely nowhere near as commanding as the reviews here would have you to believe. The plucks of a cello on a favorite Debussy recording of mine are not as punchy as those on the Monster Turbine Pro Gold. I will say it is perhaps more articulate in bass than the Monster Turbine Pro Gold, but the presence is just not there.
The best thing about the UE 900 is the cabling. The braid is genius. I do, however, have a bad connection on my left with the blue cable that causes the audio to cut out when I'm at the gym. Also, I am not sure I like the pre-formed over-the-ear rubber at the end of the cables....all this does is make it even more difficult than usual for me to put the cables over my ears. And what about those people who don't like to wear their IEMs this way? What choice have they?
In the end, I guess my disappointment is that I can go to the local Guitar Center and buy a pair of ATH-M50s that will absolutely blow away these $400 IEMs in many different ways. For $400 I should not face any compromises.