At last. This is a very exciting update. I first heard of "resumable rendering" at a Pixar presentation of Renderman 20. They call it checkpoint rendering, but it amounts to the same thing. Obviously there are some significant workflow benefits to this feature, but in particular I really appreciate the lengths ChaosGroup are going to to alleviate some of the stress in a 3D artist's life, especially when it comes to long and expensive renders that could potentially fall over at any minute, and could mean the difference between you making the rent or otherwise.
This will definitely save me a lot of time, money and heartache.