I eventually got it in the end, but it's a cumbersome affair. Oh well. Besides that, and my difficulty in getting the MMCX cable off (it's -tight- the first time round), it's all good. Minor fitting issue, due to the sharp-ish edges of the faceplate, but once I got around it, and shaping the earhooks, it's all good now.
Here's my impressions so far (2 hours or so into it):
Sound-wise, it's very good: as I said before, it's slightly V-shaped, but I'd honestly want a little bit more bass. Not sure if it'll burn-in or not (not a great believer of it), but besides the slightly anaemic bass, it's great. As I tested the IE80 a week ago, the IE80 has substantially more bass (actually so much to the point it's bloated IMO), and a slightly smaller soundstage: however, the IE80's fit and isolation was subpar compared to the UE900s. IMO, these don't work well with rock: it lacks the bass that is required to compensate for the weaker bass in rock songs. However, for classical, it's great: separation is spot-on, soundstage being greater than normal.
Accessories-wise, the UE900s deliver a significantly better package than the IE80. The number of tips is excellent, and the stems used to test each tip is ingenious. The case is a bit dumb at first, but once you develop your own 'trick' to store it (body in the 'cup'), it's surprisingly handy. The IE80 case, while looking nicer, is infinitely more bulky. In addition, the fact that the UE900s has 2 cables, one with a mic, was almost the deciding factor in winning me over compared to the IE80.
Build looks solid with the unibody design lacking any obvious weak points, but since I'm wary of past issues, I'm treating these with a very careful hand. The MMCX connectors were extremely tight to begin with, but after removing it and replacing it a few times, it's loosened up enough for removal to be easy-ish but still tight enough for most scenarios. The lack of strain reliefs disturbs me, but since the cable is swappable, I'm not too fussed about it.
I might deliver a more comprehensive review later, but right now I'm satisfied. Of course, I'm not blown away (being spoiled with my HD700's), but for an IEM, it's impressive for the price I got it for.