After giving the UE900s another try this evening (after burning them in a bit, on and off, for a day), I'm going to return them. The combination of fit (the large nozzles don't work well with my ears, making positioning difficult with anything other than the smallest silicon tips), ergonomics (the swivel cable was annoying) and very good but not mind-blowing sound just didn't justify my keeping these for what they cost. Actually, after spending more time with my C5, I realize that it actually is good enough (to more than good enough) to make the decision easy at this time. I have no problem with the fit and comfort of the C5, and it's just much easier for me to put on. Who knows - if the UE900's come down significantly in price, I might reconsider and get a pair later, but for what they go for now (close to MSRP), not worth it for me, although they obviously are great for many users.
I still don't quite understand the pinhole design, because it is so vulnerable to getting clogged. I own an earpiece dryer for my hearing aids, so with work I would hopefully have been able to keep them open, but the added hassle was another reason to wait and see. Maybe Logitech will come out with a revised version.
