As far as the physical product, CASETiFY is the real deal. I purchased one of their glitter-filled cases years ago and (thanks to unrelated water damage) the case outlasted my phone despite many drops on my part.
CASETiFY's website however leaves a little to be desired. I love their feature where you can search through an artist's designs by scrolling to the bottom of the page on a case you like. What I'm not a huge fan of is their search bar. It's not always intuitive and often leaves out some designs that surely include the search term. I fell for a case with clouds on it, tried searching for it using the search bar months later, no luck. I ended up scrolling through their entire offering and found it - a clear case with realistic clouds on it!