Oh, that makes sense! My husband recently got a hydroflask and it is like that. It was an impulse purchase at work because he didn't have a bottle on him and now that I look at it the mouth is REALLY narrow!! Our other bottles aren't like that - they're all wide mouth.
Mostly we have Camelbak and Contigo bottles but I haven't really timed them. We share a bottle when traveling so we go through cold water pretty fast; we're only good for at most a couple hours' test. I'm interested in trying out Takeya next. My favorite one for time kept at temp is an off brand one I bought while we were in China... it keeps my hot tea so hot for so long I've actually burned my tongue hours later, even in the middle of winter in Iceland.