Curtis O.wrote a review of Primus C&H Vacuum Water Bottle on June 7, 2015
Familiarity: I've used it once or twice and have initial impressions
I've always held the Nissan/Thermos stainless steel vacuum bottles as the gold standard. The Thermos 'silver bullet' (1.75 cup size) being a great companion in my ice climbing pack, keeping a hot drink available for that final, cold belay of the day.
Here's a quick, un-scientific test comparison with the Primus. From room temperature of 74F and with no pre-heating, I poured boiling tap water into the Primus (~1.25 cup size) and the Nissan/Thermos (~1.75 cup size) and screwed in the stopper and cup/cap on them. I didn't check the boiling temperature but my elevation is ~2770ft so go figure it out if you like. These full bottles were placed in a (-)05F freezer for 3.5 hrs. I then removed them and shook the contents a bit to get a good distribution of liquid temp., assuming the water near the stopper would be slightly cooler than the rest.
The result is that the Primus had cooled to ~165F (good hot drink temperature) and the Nissan/Thermos had cooled to ~175F. So, I give this Primus a pretty cool (er hot) rating. I don't give the Primus 5 stars because the screw in stopper has a spring push button mechanism to allow you to pour without unscrewing the lid. (The Nissan/Thermos is a partial unscrew to pour) In my book, keep it simple works best in nasty conditions and although you can bypass the push button stopper and just unscrew the whole stopper, relying on the spring mechanism to keep a seal in my pack with critical insulating gear is a question mark I'll need to test before I give this all five stars.
Regardless, the insulating qualities of this Primus (and the Nissan/Thermos) are far superior to the common knock off, non-vacuum, "double wall" stuff you see around in similar price range.