While google'ing to learn more about geometry issues (specifically "bowing") that I'm experiencing with my 4-month old WD-73742, I stumbled on a bit of unrelated, and very bad news. There is an inherent design flaw in (all?) Mitsubishi DLP models that eventually degrades the image quality to the point of uselessness. Specifically, the plastic components in and around the light engine slowly vaporize (due to the bulb's emitted U/V light) which eventually deposits on, thereby fogging up, the set's optical components. This video explains how to clean the affected parts (water only, apparently) and repair the problem permanently (which involves wrapping the plastic parts in copper or aluminum tape). If I'm interpreting this correctly, no recent DLP model is immune to this problem.
While I don't regret my purchase (yet), I'm beginning to lean in that direction. Especially if Mits leaves my image bowing problem out to dry (which they seem to be inclined to do).