I bought a pair of those from amercan eagle cause it was the only kind they had in the color/fade I wanted.
They are pretty damn weird. It feels like you are wearing pajama pants. They are lighter, and pretty dang comfortable, but I prefer the feel of standard jeans.
And you better wear a belt with them, or you will be constantly pulling them up after a couple hours of wear.
The girl at AE said they are moving all of their pants to the stretch fabric. I don't like that, but it's smart from a business standpoint, as it should reduce returns due to shrinkage. A lot of people buy pants that just barely fit, and if they shrink, as cotton tends to do, they return them.