Not sure about horror stories beyond the lamp needing occasional replacement which you are already well aware of with your Sony which is, essentially, a DLP.
Well, yes, of course the rear pros need the lamp replacement as a routine every few years, but that's not what these folks were describing as "horror stories" with regard to the Mitsubishis; they were more or less saying they don't last long and have rainbow/light output issues and other problems...and, of course, that the image isn't as "sharp" or "in your face" as a flat panel. That could all be opinion, though.
As for my Sony SXRD, yes, I am aware it needs a lamp replacement every so often; and while not marketed as a tried-and-true "DLP" set, the SXRD technology is indeed part of the microdisplay subcategory in the newer rear projection displays, using the "SXRAD" chip design, or what Sony likes to call "their version of LCoS."
But Mits dropped ALL other tech besides the DLP so what does that tell you? I'll take DLP over other tech any day of the week as it is closest to CRT without all the maintenance required such as convergence, but still maintains the smoothness and film-like qualities that EVERY TV maker strives for.
Well, from what I understand and have gathered from attending press conferences at CES and CEDIA, Mitsubishi got out of the flat panel (LCD/plasma) category not because these technologies "don't work" or they didn't believe in them; it was merely because they want to be regarded as the ultimate BIG, big screen company, offering buyers a real alternative to front projection if they want to stick with a TV screen, with the choices of massive screen sizes up to 92 inches. Many marketing heads at the company openly admitted in press conferences and events that Mitsubishi simply could not keep up with the amount of flat panel TVs companies like Samsung and Sony were selling, so they decided to go a different route and offer massive rear projection sets as the go-to brand for huge television displays.