The Ember Smart Mug 2 is niche, but it has a loyal following. Even though we think there are better mug warmers on the market, Ember is like Apple AirPods or Kleenex. People want what they want. Right now, for Mother's Day, the Ember Smart Mug 2 is on sale for just under $100, a 30 percent discount and a match of the very best price we've tracked. You can save at Amazon, Best Buy, and the manufacturer's website.

This smart mug is probably overkill. It has a smartphone app that notifies you when your coffee reaches the ideal temperature, and its onboard light also provides a visual indicator that your brew is ready. It intelligently adjusts power usage to keep your drink warm when you're nearby, and turns off when you're not around. The self-heating mug is on sale in a few variations—10 or 14 ounces, in blue, white, black, and purple.

The mug offers up to 80 minutes of powered heating time, or you can pop it on the included charging coaster to keep the battery going all day. And you don't need the smartphone app unless you want to precisely dictate your coffee temperature—the mug defaults to 135 degrees Fahrenheit without your specific input.

Our main gripe is that this proprietary warming system is not dishwasher safe. You need to hand-wash each component, and ensure you do so carefully, because the items are not cheap to replace. But if Mom has been putzing around the house drinking perpetually microwaved coffee, perhaps an upgrade is in order. We have additional recommendations in our guide to the Best Coffee Warmers. You may also want to check our related stories on the Best Espresso Machines, Best Coffee Machines, and Best Pod Coffee Makers.