I just ordered the k3003; they'll be here tomorrow.
I've been listening with the ie80 and um3x for the past year or so, and am really hoping for something better. I find the ie80 to be too dark, murky, and laid back - although Carbon Based Lifeforms sounds reasonably decent. The um3x, while excellent for certain source material (e.g. Andy Summers & Robert Fripp - I Advance Masked), yields over-powering vocals and a claustrophobic soundstage.
After I've had a proper chance to evaluate them, I'll post my thoughts to the impressions thread.