I love this mug! In my experience it has been perfect; completely leak-proof while keeping my coffee hot for hours. I will say that I DO NOT think the lid is dishwasher safe. I washed it once in my dishwasher and I'm pretty sure the little rubber piece (that I failed to notice when I first got the mug) that fits on the stopper fell off, thus not causing the lid to not seal at all. However, when I contacted Stanley about the problem they sent me a replacement mug at no charge! I will NEVER buy another mug...unless it is another Classic One Hand Vacuum Mug!
I own 3 of these. Best coffee mugs I've ever owned. There so good, my wife bought 2 for her self. I work out side. In a dirty, dangerous, drop things along way down job. I've abused these mugs for 3 years. And finally need to replace 1 lid. And believe me, I've abused these mugs. I don't stick cup in dish washer, or lid. Stop being lazy.
Button on mine keeps popping off. Can put back in but is useless unless you find the little spring. This started happening about 6 months. Now the seal is missing & leaks. Don't normally search my sink after I wash dishes so, I guess bye bye. Light use, don't abuse it.
The performance is as good as the more expensive lifestyle mugs, but it doesnt spill. I am bus and I don't have time or patience for spills.
the cap started to malfunction and now it spills. the button will get stuck and i definitely don't trust it to keep us dry while using it.
I bought two of these at Starbucks. The button broke off on one, and within a week the button broke on the second. My use was easy, so this definitely is a design defect.