Perhaps I haven't been at this long enough, or maybe it's my usage pattern (low lumen/runtime enthusiast), but all my lights have been reliable with the only real field failures I can recall were incan bulbs burning out and a 17670 PCB failure when dropped while inside a light. I have returned a few lights that were faulty out the box, however, including my first Malkoff - go figure.
Of my collection of 1xAA/14500/sub-lumen lights (~2 dozen), it certain does SEEM that my Malkoff MDC AA and Peak El Cap are tougher than any of my Asian-manufactured lights, but without any real failures, the built proof tank-like build of the US lights is a little lost on me and adds significant bulk/weight, while reducing features/performance/versatility.
I'm going to vote for Foursevens (Quarks in particular) which, for me anyways, provides the best combination of Asian features/performance/versatility AND is "reliable-enough" and backed by a real US warranty/customer service/location. Will my Quarks outlast my Malkoffs or Peak? I doubt it, for one, I use them A LOT more
, but I also have lots of Lego parts, and carry a back-up light or two that have never been used for their intended purpose.
Any light can fail, the question is who will take care of you. In that regard, I consider my "US-backed" lights (US-made + 47s) to be warranty repairable, while my "Asian-backed" lights to borderline disposable.