If it's metal and it's used to hold or prepare food, Zojirushi has it dialed in. Their vacuum bottles have always been first rate, and you can bet your bottom dollar that whatever you put in them will be hot or cold as you prefer when you want it.
The new Zojirushi 600ml/20oz stainless vacuum mug is a vacuum bottle with one of their very cool selection of lids on it. This lid has a toggle-style switch on the front, right where your thumb wants it to be. An easy press and the lid pops back on a hinge, revealing a little shaped drinking surface that maximizes lip lock like a hormonal teenager, and minimizes spill.
Speaking of spillage, you'll get none here so move along. When closed you can lock the lid in place with another smaller toggle switch, so it would be very difficult to accidentally activate the lid. Contents will be close enough to starting temperature for the better part of a day; they say six hours, we say at least that long.
There's even a nonstick-coated interior to guard against those salt-heavy energy drinks if that's your thing. And speaking of sticky, the exterior coating has a nice grip to it, not tacky at all but definitely not slick either. So let's recap: Zojirushi knows their stuff = their vacuum bottles rule = get this mug if you need a spill-proof travel companion in your car or in your backpack.