I finally broke down a few years ago and let my wife buy a Purple. I thought for sure I'd hate it. Damn thing comes rolled up! Turns out I love it! It doesn't have any of that annoying memory foam feeling and is pretty supportive. My only complaint is the side walls aren't terribly firm. I sit on the edge of the bed a lot and have 3 kids that will pile in and force me to sleep on the edge. It could use a bit more support on the sides. But otherwise, its been super nice.
We haven't had any problems with extra dust a few years into owning it. And it doesn't yet have any sunken spots.
PS - we previously had a super high-end name brand mattress that we shopped around for, tried out in store and spend a couple grand on. We like the purple better.