I tried these out today and was not blown away. While they do sound good, I don't think they sound as good as some others brands I've tried in the $99.00 - $199.00 price range.
They are bright and loud but I think the bass is a little low (at least for my liking). The highs can be a bit piercing at times too. At lower volmes, these don't perform as well. The sweet spot on the volume seems to be around 65% -70%. The cable is not as much of a hassle as others have posted. However, I agree that my ears started to feel a little sore after wearing these for 45 minutes. I also got the sensation they were falling out, when in reality they weren't.
Lots of extra ear cushions and extra cable is a nice feature. Nice packaging too. BUT, I think thats where the money went on these.
As an experienced in-ear headphone user, I am disappointed in the UE900. I really found the sound signature detailed, warm (but not too warm) and almost balanced (slight V-shaped, but not to its detriment). However, from a design POV, I can't recommend it. For one thing, I absolutely detest the memory wire on the cable. No matter how much I fooled with it, I could not get it to stay in the crease of the backside of my ear. That was annoying enough, really. They just felt like they were not secured.
In a related issue, I am not a fan of the swivel cable connection (sent back the Shure SE425s in part for the same reason). Why anyone finds it necessary to design a $400 IEM with the swivel cable is beyond me. I experienced some early issues with sound cutting out, but even when I finally figured it out, I was not happy with the swivel idea. Not only is it another potential moving part to go bad, it also eliminates the option of a different cable (although UE cables are not standard, even the two-pin ones).
Also, as the other reviewer noted, the insertion depth is pretty shallow, which is comfy, but also gives one the feeling that the tips are sliding out of your ears the longer you wear them. It's sort of illusory, but being used to customs (JH5s). When you combine the shallow insertion with the memory wire, they just don't feel snug on your ears/head.
When on the go, I like a snug over the ear cable, good isolation and most of all, an IEM that is not going to keep distracting you from the music, which is how I found the UE900s. A real shame, because they do sound very good.