The only minor downside is the lid design, but it's a solid choice overall. The tumbler fits perfectly in my car’s cup holder. Construction is very sturdy.

Double-wall vacuum insulation works really well. This one is larger and better insulated. It keeps scalding hot liquid, scalded hot for hours!

Spill-proof the lid fits securely and doesn’t leak, even when i toss it in my bag. Cleans easily in the dishwasher or by hand. Only issue with the cup is the difficulty of cleaning the lid under the sliding mouth piece. Has a great seal, no spills.

This cup has no airflow vent so drinking your coffee takes forever. The lid's o-ring on the sunwill mug is undersized and does not provide enough friction to keep the lid closed. Only way to use is cover and leave mouth spout open.

Even after soaking and washing it. The sliding cap is not able to be easily removed. The sliding piece on the lid is impossible to clean unless it's popped off.