There's a group buy going for this on the *************** (is it ok to mention that forum?). Looking, however, at some of the posts for the 1080 (I'm in exactly the same situation you're in, looking to add HD asap), it appears that there are several glitches with the Zenith (loss of menus, software incompatibility with DirecTV that may or may not be resolved, and having to push buttons on the back of the unit in the course of normal operations). I also have read on this forum that the Panasonic is real good for upconverting and PQ. Then, a lot of people also seem to like the Toshiba. Then, there's the fact that both Samsung and Zenith are coming out with new units this June and August, respectively, with at least DVI connections among a whole lot of other enhancements.
At this point, I'm clueless as to which way to go--buy now, and what? or wait another three or four months (which I don't really want to do).