Pretty designs (and a lot to choose from) on both sides. I like to roll my mat out on opposite sides each time I use it to keep it from developing a permanent curl on the ends from always being rolled up the same way. These reversible mats give me pretty designs to do my yoga on each time. It's the little things.
Perfect thickness. Thick enough you get the padding you need. Not so thick that your balance is thrown off during poses.
Durable. I've had my mat for almost 3 years and still no signs of wear and tear. And I use it very regularly!