I have been using these paints professionally for over a year. I find them a bit more challenging than regular paint, but that's ok given the incredible finish they produce. I'm surprised by so many negative comments from consumers and can only wonder if the poor results are due to a lack of experience rather than a poor product.
Yes, the paints are expensive. Yes, they are different. You cannot cheat your way into them. I've found that neither the suede nor the river rock looks nice with just one roller coat (streaks, uneven coverage, etc.), however most lower-cost paints will not look nice either after one coat.
I've also found the directions on the can to be over-simplified, especially for the suedes. It seems that the "X" brush stroke that is recommended for the second coat doesn't make a suede-look at all; instead, it just makes a bunch of X's on the wall! Use a different tool to get the suede effect.