Oops - left that part out of my reply. My synthetic bags usually died after a year or three of moderate use; longevity was one reason I sprung for a good down bag when I could afford it. I fully agree with you and Keith that a good down bag will outlast a good synthetic. (I can't speak to whether a second-tier down bag will outlast a first-tier synthetic since I never owned a second-tier down bag.)

I guess my point was more in the nature of affordability: I remember a time when I couldn't afford $400 all at once for a good down bag, but could afford $100 - $150 every two or three years for a good synthetic bag. Within those constraints (and recognizing that if I could have made the synthetic last for 5 or 6 years, I could have saved up), I'd choose a good synthetic over a mediocre down bag.

When I no longer had to operate within those constraints, there was no longer any hesitation: I gladly forked over the money for a good down bag.