I bought my Polar White one (used) a few months after launch and it developed a crack on the left hinge months ago. I never dropped or abused it. In fact it was just sitting in a drawer before I noticed the crack. Also the shoulder buttons and rubber feet have turned into Urine Yellow. I think I might buy a replacement casing for it.
I also bought a brand new Onyx Black a few days ago so I hope these newer batches don't crack.