Blender 2.78 released not too long ago, but a few major bugs were discovered since then, despite a strong internal QA push before it launched. As such, Blender has released 2.78a. In a way, it has some benefits. NVIDIA wasn't able to release the final CUDA 8 SDK in time, so Blender 2.78 shipped with the RC SDK, and it was only enabled for Pascal-based cards. This extra month allowed them to roll it in and enable it for all cards, although it probably won't affect the end-user in any major way.
The release notes claim that 69 bugs were fixed, several of which were crashes and hangs. I have never really experienced any of these, but those who do should, obviously, appreciate the patch. As always, Blender is free, so enjoy creating.
Seriously. If you have free time and the slightest bit of interest: Go do it.