OK, before you get all excited, these "yoga mat" flip-flops are not made from recycled yoga mats. They are simply made from "yoga mat" material. Since yoga mats are made from a variety of different materials, these are some sort of cushy synthetic that has a "springy" quality like a thick, plush yoga mat. (Actually, I find most yoga mats to be a bit more stuff than these shoes.)
Some people swear by these flip-flops - and indeed, if you like a simple, basic flip-flop (or "thong") without a lot of bells and whistles, and you are willing to pay around $30 for a pair, these are for you.
They are pretty comfortable for a basic flip-flop.
These shoes have quite a few negatives, however. One is that they do not have any real arch support - not that people who are looking for arch supports go to flip-flops as their first go-to, but "orthotic" these are not. The other issue is that these shoes are really not made to get wet. Some have complained they get downright "squishy" and even "foamy" when confronted with any sizeable amount of water. These are not flip-flops that are really made for the pool area, unless you are one of those folks who doesn't get wet - but if you regularly put dripping feet into flip-flops once exiting the pool, these are not the shoes to do that in.
Personally, after enjoying my Sanuks for a few years, I am sadly giving them away because flip-flops are now causing foot pain for me. The Sanuks are still in great condition, however, after a good deal of use. I have read some reviews of Sanuk that seem to suggest that the quality may have gone down recently, but let's hope those were anomalies.
Overall, for a basic flip-flop, these are better than average. They are great for lounging around, or going to and from yoga class. However, if you really want to do your feet a favor, get some more supportive sandals for extensive walking sessions. Flip-flops are really bad for your feet...I've learned that the hard way.