I have owned a number of them over the years. Last I heard they were all working fine. I have a 2009 82" Mits which almost never gets powered up and my 2011 92" which has the 7 thousand hours on. It is a nosiy cantankerous beast and works great except for the occasional shutdown over something it doesn't like coming in on HDMI. I have had extremely good luck with HP, Samsung and Mits sets. I expect the 92" to be in main service until I can buy a similar sized UHD set for under $4K. I am in extended warranty for another year and a half. I run my DLP sets on high quality UPSes.
Are there things about them I hate? Sure, but I like large displays and they were the only affordable quality image available at the time.
High Energy Usage
No Instant on
No Instant off
Poor Blacks, relative to good plasma and good LED
Noisy chassis. The 92" Mits especially makes more creaks and groans than a 100 year old man getting up in the morning
Lack of confidence in reliability (despite my personal experience to the contrary)
Did I mention overscan and geometry issues.
Constrained light output. The 92" makes more light than the 82" but Mits "underlamped" their very big displays.
Overall bang for the buck
Film like picture
Most of the important issues with Rear Projection are in the implementation. Mits was under so much price pressure in the late years that they did not really build the kind of chassis that the really big sets needed. A better built set could have eliminated many of the irritations I find with these sets. Stout chassis, with stiffer screens, bigger lamps, better and quieter ventilation would have been worth an extra grand on the price.
Samsung 78" JS8600, Mits WD-92840 43" Samsung 43ku7000 - Lumagen Radiance XS, Martin Logan Motion 40s, Ascend Sierra 2s
58" Panny Plasma -DVDO DUO, Usher S520, JBL HLS-610, Definitive SM45, MusicHall Marimba