The first thing that I found that was so great about Adobe After Effects CS6 was the caching ability. In prior versions you would have to just wait for it to render. Now you can cache on one project while working on another. What I also like is the fact that once you do a full render, when you change things, it only has to render what was changed - even if you save and come back in at a later time!
Another powerful feature is the integration with Illustrator and the ability to adjust attributes directly from within After Effects without having to return to Illustrator - another big time saver. Then there is the Ray-traced 3D rendering engine. The capabilities are much more accurate and it is so much more powerful than the one that came with CS5.5 – which is still available and now known as the classic renderer.
Then there is the 3D Camera Tracker which can build a virtual camera inside of imported footage while automatically figuring out how the original camera tracked and how it relates to the scene. As in the images above, you can take multiple monitors and overdub other sequences on to each one and as the camera in the scene moves the added sequences stay in step.
When you add the feathered soft edge to masked shapes, Rolling Shutter artifacts adjustments, import abilities, new effects, and all of the other improvements, what you have is a major winner with Adobe After Effects CS6. Whether you are considering a new purchase or an upgrade, I very highly recommend this product.