Waaaaaayyyyy back when I posted this (holy crap, it's been a VERY long time now ) there was no other evidence to go on other than actual user comments. The trend was indeed that users with the "5" ending weren't having issues, the ones with "zeros" were. As blee states, the sample is small, but it's the only sample we have.
Do things "have to make sense" to be true? Not necessarily. Perhaps they were put together at different places, or at different times, or in a different manner, or (insert causality.)
Fact is, that this tech is still relatively new and has a small target market. Hell, projectors in general are a small market item, given that so many seem to be content with a itty-bitty TV at the same price or even more. All I know is that I have not had one single regret since purchase. It's beyond phenomenal that I can have a huge image and have absolutely ZERO worries or maintenence concerns for years. Having just hit 4,200 hours, we would surely have replaced a bulb or two in a conventional unit. Ours still looks the exact same as the day we opened it...gorgeous.
Side note: I've never, ever, NOT EVEN ONCE, thought about nor noticed the so-called "fan noise."