Bests & Worsts Reviews from Amazon

This is by far the best insulated coffee mug I've found. I now have three of them for various reasons. There are a few design problems, several of which have been pointed out by other reviews. 1) It's hard to see where the sip holes are, so you can spill liquid on yourself if you get that wrong. Fix: see the image attached. I used a black paint pen to put dots where the sip holes are. Very durable, and easily reapplied if they eventually fade. Another reviewer drilled holes, but although I like the permanence of that solution, it seems like it might be hard to clean. 2) If you rest the cup on any surface that is not level (such as an airline tray table) it can easily slip Fix: see the image. I used a cutout from some self-adhesive speaker non-stick bottoms pads. It has about 2 mm of foam as well. This seems to work perfectly. I applied a thin film of epoxy to the bottom of the mug before applying the pad, since I've learned without this trick they will come off in about 6 months. 3) Even with the paint dots on the lid, it would be nice to have tactile feedback that you are going to have your mouth at the right place. Fix: see the image; I cut out ellipses of indoor/outdoor velcro (hook side) and affixed one on each side of the mug. I put them so that once the mug lid is fully tight on the mug, the dots align with the ellipses. So this gives an extra bonus of providing a cue as to when the lid is on tight enough to prevent leaking. For new mugs, I slightly over tighten since the gaskets do relax a bit over time (maybe about 15 deg). Now just by picking up the mug you have feedback as to where to drink out of the mug. Finally, I believe the care instructions indicated not to put the metal part of the mug in the dishwasher. Regardless, I've found that doing so damages a smooth interior finish that makes cleaning the cup easier. I recommend only hand washing the metal component.