So, as most have posted, yes a stainless steel vacuum bottle for hot beverages is a lovely luxury, but like all luxuries, it comes with a price tag: Extra weight.
Somewhere in this thread, someone posted their experience with their wide-mouth thermos not maintaining heat for very long compared to the small-mouth variety. I am hoping to rejuvenate this question so some of the scientist/physicist(sp?) types here can unravel this mystery for the rest of us "less-than-astute" folk.
I wonder if it has to do with the larger surface area of the opening not being so well insulated as the majority of the container. MAYBE the heat is being lost there?
Also, i can attest to "wicked hot" coffee for prolly 18 hours and very warm coffee at the 24hr mark. I love my $4 EMS 1.5 liter stainless steel thermos and the other $7 1 liter stainless steel thermos's (i bought two at that price!!!!) i managed to grab as a PT gear-slinger there.
I'd say buy one - you'll likely not regret it.
fm