The cool thing about them is that they actually fit my feet. I have fairly short and broad feet, and I wear a 10 and a half. So I figured I'd get a 10 since they are a stretchy material. The surface is flexible enough for you to be able to move pretty much unimpeded. It has a pretty good grip so you can use them on pretty much any surface. They're pretty quiet if you move right. Over all, a great martial arts shoe... however...

My only complaints are

1) that the entire shoe is made of roughly the same stretchy elastic-polyester material. This makes the heel act funny, because your foot doesn't settle all the way to the back of the rubber sole, it gets pushed forward by the elastic material.

2) the opening for your foot is just small enough to be a pain to put on, and just big enough to slip when you move too much.

Both of these could really be because of the size of my feet, which is kind of akward. So aside from issues due to proportion (which is always an issue on factory footwear, or clothes of any kind), these are GREAT shoes.

For a fair comparison, I also bought the cotton soled shoes. The cotton soled shoes are actually a little less flexible, due to the thickness of the soles (which are layered cotton, so it's pretty much like walking on a laminate of fibers). The shoe itself is more or less the same, but the proportions are a little different. The shoe is longer and thinner, so people like me with hobbit feet end up having a big pointy empty spot at the end of the shoe. The soles are very slick, so they are dangerous on slippery surfaces like wood or tile.
All in all, I like the rubber soled ones better, but the cotton soled ones are also quite good. At the price, if they wear out (which they will after a month of solid practice) you just replace them at their nice cheap price. If you feel like you are going to be doing a lot of practicing you might stockpile them, as the shipping would be cheaper. But try them out first before you commit to them (2.95 shipping is a good chance to try things).