I moved into a house with RL on every wall and it looks fantastic - everyone raves about it. I recently applied 2 coats of river rock paint to a new wall - it was a breeze and looks great. It dries quickly - I think maybe people are trying to roll over a partially dry section to get a missed spot - bad idea, it'll leave a line every time. Wait until the wall dries and get it with the second coat. And don't press the roller too hard because that will leave a line as well. Work fast and use even pressure and you shouldn't have a problem.