(news & commentary)
Several bugs were fixed. There is new compact and mirrorless camera support, but no new Nikon bodies are supported, as Adobe was already current on that. There are new lens profiles, though, including for the Coolpix A, Coolpix P330, the 80-400mm, and for the Sigma 17-70mm f/2.8-4 and the Zeiss 135mm f/2.
This release is the first of the "forked" releases of Camera Raw. Creative Cloud users get a slightly different version of Camera Raw than do Photoshop CS6 users. Basically, Adobe will provide bug fixes and new camera/lens support for CS6 users, but add no new features as they will with Photoshop CC. This introduces a whole new problem in and of itself. Both releases are version 8.1. Therefore, if you write about, or need support for Camera Raw, you're going to need to specify ACR 8.1 CS or ACR 8.1 CC to distinguish the version you're using.
Let's see, one of Adobe's stated reasons for Creative Cloud was to keep from maintaining separate code bases. Yet even before Creative Cloud ships here we are with another diverged code base. It's this kind of mumbo jumbo marketing that is causing Adobe so much grief right now: can you actually believe anything Adobe is saying when they keep contradicting themselves?
Along with Camera Raw 8.1, DNG Converter 8.1 also shipped. If you use Photoshop CS3, CS4, or CS5, you can use DNG Converter to do your raw conversion for new cameras.