First, a warning: The Amazon product description currently displayed is NOT correct for this product. It does not have a steam valve and the lid does not double as a cup. It does not keep a beverage hot for 5 hours.
That said, here is a review for the actual product pictured:
I am always on the lookout for the perfect travel mug - and I have yet to find it! This Innate tumbler is very close, though. Here are the criteria I use to judge travel mugs in general, and my thoughts on the Innate in particular:
* Not too large or too small (Innate is just the right size - great for about 10 oz of liquid, with a little room to spare.)
* Easy to clean (Innate is perfect - no nooks or crannies to accumulate coffee grime. Very easy to clean.)
* Simple drinking mechanism (Again, Innate is perfect - no complicated buttons to press or small parts to break. Works well.)
* Relatively leak-proof (The Innate is pretty good - as long as you keep it relatively vertical, it doesn't seem to leak.)
* Keeps my drink hot for a relatively long period of time (This is the only possible shortcoming. I'd say that my coffee cools off a bit too quickly with the Innate.)
The other travel mug/tumbler that has come closest to perfection is the Nissan/Thermos vacuum tumbler (Thermos Nissan 12 Ounce Stainless Steel Tumbler The Nissan does a much better job of keeping my drink hot - it literally keeps it hot for hours, with no preheating needed. Plus, it's 100% leak-proof - you can throw it in a bag all day and it won't spill a drop, even it it's upside down. But, it's harder to clean, with multiple seals and two lid pieces, and a hole in the base plastic that traps water. I guess I'd have to pick the Nissan over the Innate, but you might enjoy using both, as I do.
Overall, this is a nice little travel tumbler, which I'd recommend as long as you don't require super-piping-hot beverages or 100% leakproofness!