The Good: The Ember Travel Mug precisely controls its beverage temperature. It has an alluring, distinctive design. Coffee it held at optimal temperatures had plenty of flavor. The Bad: It's outrageously expensive and doesn't hold much liquid. Away from its charger it retains heat for two hours or less. It uses a proprietary charging system. The Bottom Line: Only ultra-rich coffee geeks should risk getting burned by the Ember mug's flashy temperature tech and insanely high price. There's a Goldilocks zone for drinking hot beverages. Coffee or tea that's just out of the brewer will scald your tongue. Lukewarm drinks meant to be piping hot are never satisfying. When they're at their ideal heat level though something magical happens. Given quality coffee grounds and a competent coffee maker, you can taste a pleasing depth of flavors. That's just what the $150 Ember Travel Mug is designed to maintain by way of sophisticated electronics and clever engineering that actively regulate the temperature of the mug's contents to a precise degree. The good news is that the Ember actually works. Coffee from the Ember was particularly delicious, so much so that it was hard for me to stop using it. The bad news, besides its outrageously steep price, is that it doesn't work for long. Away from its powered cradle, the Ember quickly runs out of power and heat. The 12-ounce container doesn't hold much coffee, either. Both are serious flaws in any travel mug no matter how fancy it is. So unless you're a hopeless coffee fanatic or you like pouring money down the drain, you're better off sticking with an ordinary $20 thermal mug.A 21st century cup?At first glance the Ember Travel Mug may look like an ordinary single-serve thermos. Tall and slender, the mug has an exterior that's all black. About a third of the way down its length, the Ember tapers to an even thinner width. This change in diameter is subtle but important. The mug narrows slightly above where your fingers naturally fall on it, which helps to stabilize your grip. The Ember's matte surface also works to reduce slippage. It's entirely devoid of gloss, reflections or fingerprints. The surface feels comfortable, too, and it also wicks away moisture. I also like the cap that has a slick, spring-loaded lid you push to open and close. You can drink it from any direction.This is one dense cup, though. The Ember weighs a hefty 1 pound when empty. Filled to its full 12-ounce (0.35-liter) capacity that figure rises to 1.75 pounds. It's a handful for sure. The second piece of the Ember beverage system is its charging coaster. Flat and rectangular, the pad is black with a matte skin that matches the cup. A receptacle on the coaster accepts the Travel Mug and charges its battery. Be advised that the coaster's mug interface (tiny metal contacts) and its power cord are proprietary. That's a shame. It would be extremely useful if you could charge the Ember wirelessly like you would a phone. You might own one of these universal charging pads already. The technology is also working its way into cars, furniture and even home countertops. As it stands, your only options for charging the mug in multiple locations (say, at home and again at the office) is to carry the coaster with you or buy an extra one for another $40.Life with the EmberYou start to use the Ember Travel Mug as you would any cup. Unscrew the top and pour your drink inside. At this point things get interesting. The "Ember" logo on the face of the mug is really a touch-sensitive button. Touching it for five seconds powers the device on and off. A quick logo tap activates a small screen of white LEDs. The display is near the bottom of the mug and recessed beneath its surface.