CINEMA 4D R14 not only builds on the foundations of R13, but it also brings some exciting new features that are really welcome. First and foremost is the new sculpting tools and workflow. The whole sculpting user interface has changed dramatically and now gives you both much more freedom as well as control on everything you do. They are very easy to pick up on if you are familiar with the CINEMA way of doing things and they are a lot of fun to work with.
The ability to work with and round trip in Adobe After Effects has been improved upon, but now you also have the ability to work with CINEMA 4D files in Adobe Photoshop as well. This gives you a lot more power when working in R14. Then the Camera Calibrator is a great new feature as well giving you the ability to orientate your scene based on the contents of a photo.
These items alone make this upgrade worth the price as it is, but when you add in some of the other items such as the camera motion tags, Radiosity maps, improvements to XPresso, Shift-C Commander, and all the other items listed above, I think this update is a true no-brainer and so I highly recommend CINEMA 4D R14.