Those 11 hour runtimes are of usable light. It might be 5 hours full output and 6 hours dimming.
The lower price is due to not having to completely redesign a light. They changed the incandescent bulb to a Seoul P4 LED with a regulator and a heat detector.
If you think the surefire have good output to price, then you haven't seen some of the other cheap lights. A light I have outputs at least 120 lumen(If I spent $10 for a Cree Q5, this figure should go up to about 160-170 lumen) for an hour or 20+ lumen for 10 hours, all this in a $25 light(well, $35 including batteries and charger). But of course, the build quality(but it has been literally kicked around, thrown around and dropped and it still works fine), customer service and development time is not as good as Surefire's. The only thing it has compared to Surefire is price and output.
What kind of light you'll need all depends on what it will be used for and what kind of abuse it will see.
Surefire lights are basically bomb proof(except for their clickes, 24% failure rate according to
this thread).
Fenix lights are good all arounders and they improve relatively quickly.
Cheaper lights all depend on the brand(Ultrafire, EastwardYJ, MTE are pretty reliable ones from what I have seen), model and luck of the draw, but they do change very quickly.
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