There's far less feedback out there for plastic travel mugs than there is for stainless-steel mugs (which are covered in their own section). They don't get nearly as many recommendations on retail sites as the most popular stainless-steel mugs, and most professional tests don't cover them at all. TheSweethome.com, for example, chose to exclude plastic travel mugs from its tests because earlier tests at Cook's Illustrated and Good Housekeeping showed that they can't retain heat for much more than an hour, and they also tend to break easily. Good Housekeeping's test from 2010 includes some plastic travel mugs, but they don't perform nearly as well as the stainless-steel variety. And user reviews for plastic mugs, even the most popular ones, complain that they tend to retain odors over time, even with regular washing.
Still, plastic travel mugs offer a few advantages of their own. For starters, they're significantly less expensive – so if you accidentally leave your mug behind on the subway, you're only out $10 or so. They're also lighter than many stainless-steel mugs, usually weighing no more than 8 ounces for a mug with a 16-ounce capacity. And finally, many plastic travel mugs are microwave-safe and dishwasher-safe – though not all are, so you should check the instructions carefully.
If you think a plastic travel mug meets your needs better than a stainless-steel one, your best choice is the OXO Good Grips Double Wall Travel Mug (Est. $12) (formerly known as the Plastic Liquiseal Travel Mug). This 15-ounce mug, available in a five colors, is the only still-available plastic travel mug that earned fairly high marks in Good Housekeeping's 2010 tests. Editors are impressed with its locking-top, which opens up for a sip when you push a button and seals again as soon as the button is released, making it virtually spillproof. They also say the mug is comfortable to hold and drink from and doesn't obstruct your view as you sip.
However, like all plastic travel mugs, the OXO Good Grips has some downsides. While it's great at keeping cold drinks cold, it does only an average job of keeping coffee hot -- though that's still better than most plastic travel mugs. It also dented during Good Housekeeping's drop tests. Unlike some plastic travel mugs, the OXO mug must be washed by hand, and several reviewers at Amazon.com say the lid is hard to clean. Also, the mug is not microwave-safe, though a couple of Amazon users say they have nuked it without incident.
If a mug that can't go in the dishwasher or the microwave is a deal-breaker for you, the Aladdin Transform Recycled and Recyclable Travel Mug (Est. $10) is a reasonable option. This colorful, 16-ounce travel mug is designed for convenience, with an easy-to-grasp handle, a shape that fits most cup holders, and a flip-top lid that flips open for sipping and shuts when you flip it back. It's also eco-friendly, made from 97 percent recycled plastic that can be recycled again when the mug wears out. Editors at Good Housekeeping say this travel mug is stable, comfortable to use, and easy to open and close. However, it also leaked and cracked in their tests, and it wasn't able to keep drinks hot or cold for every long.
Another budget-friendly option is the Copco Acadia Mug (Est. $8.50), which isn't covered in professional tests but has a lot of feedback, most of it positive, on Amazon.com. This eye-catching travel mug is designed to look like a paper or Styrofoam coffee cup, but it's actually made from double-walled plastic, with a grippy textured sleeve in a choice of eight colors. It's also microwave- and dishwasher-safe (except for the lid, which must be washed by hand). Most users say this travel mug is a good value: reasonably sturdy and comfortable to hold, with a secure-fitting lid. However, several owners say the mug doesn't hold heat well, and since its drinking spout is always open, leaks or spills are common. Also, there are quite a few complaints that the plastic starts to retain tastes and smells over time, even with regular washing.