I have never used an L.L. Bean bag, but have heavily used a 0° Marmot bag for 15 years, in all seasons. It is still in perfect condition, huge loft, and ferociously warm.

I recently replaced it, to shave off a pound of bag weight, with a new 0° model from Marmot.

L.L. Bean's offering would have to be a very high quality product to compare well to Marmot.
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It's easy to be a holy man on top of a mountain.
-- Larry Darrell