[quotemsg=17987008,0,10899]They lasted me about 10 years before something inside them finally died (probably capacitors).[/quotemsg]
I did a tear-down of my BX1000 two years ago and 10 years is just about how long it lasted before it started freaking out. I plan to investigate what went wrong and possibly fix it in the near-future. My initial suspicion says caps too, even though most are Nippon Chemi-Con if I remember correctly.
[quotemsg=17988960,0,2250969]Would love to see a tear-down of a "home theater" UPS - are they really better/different than a standard UPS for computers? Example: APC's S15[/quotemsg]
While there is little doubt that they are better, the real question are: how much so and how different do they need to be to do so? Most of the answer for the first question can be inferred from the spec sheets: multiple AVR buck/boost ratios to provide actual line voltage regulation instead of the one-step buck/boost in typical UPS, extra output filtering, surge suppression, etc. The second one is trickier since there is a handful of ways most of the differences can be implemented and I can imagine how UPS engineers may get creative with component re-use in a consumer UPS to implement more features using few to no additional parts.
An even bigger question is: are those really necessary? The bulk of modern AV equipment uses switching supplies too. There isn't much point in having super-clean 50/60Hz when the first thing you do is introduce broadband 0Hz-1MHz noise with a switching supply and then filter that again.