I own both this version and the flip-top version of this. They both keep the temperature of the contents quite well; however this one has less parts to keep clean and is easier to clean. Also, if you transport soups in these you're more likely to store chunky soups in this one. While you can unscrew the flip-top one too, this one comes with a mouth-friendly plastic piece that covers the top metal edge of the container.
This is a 2-piece design, when you want to drink out of it you will need to screw the top. This means you have to hold (or put down somewhere) the top while you consume. In contrast the flip-top you just flip it open and the top stays attached to the container. But then as for the flip-top I found that I was hitting my nose right on the part of the top that was covering the hole to the container and since it always had a drop of liquid on it always wound up on my nose unless I either tip my head back further or suck on the top (which in of itself felt weird to do). Anyways back to the 2-piece product... its opening is relatively the same size as a flute-type glass (think champagne), which tends to make your head tilt back since the far edge will hit your nose.
If you're washing the top just before filling it up be sure to shake the excess water out of the top or it may appear to leak but not really it's just excess water coming out from the other side of the outer part of the top. If you aren't Japanese about keeping your mug clean you may be giving a chance for it to become gummed-up and gross. If you don't abuse it during use the seals will last long enough to just buy another mug when they wear out, years down the road.
Look for the Zojirushi logo and quality control sticker on the bottom. The inside of the mug is highly polished as well. Don't accept any substitute.
Zojirushi's stainless steel vacuum insulation will keep your beverages hot or cold for hours. Each stainless steel mug has a plastic cover around the mouth and an easy to clean Slick Steel finish interior that resists corrosion and repels stains. The compact design of this mug takes minimal space while maximizing capacity.