I made the switch to PS CC on the $9.99/month plan for several reasons. One of the most important is that the new image resizing algorithms are much better (and, I believe, not available on CS6). I have been using Genuine Fractals, now called Perfect Resize, for years to up-res files. A "smart" up-res of 200% effectively increases the signal to noise ratio and is particularly valuable whenever one is going to alter the geometry of a file, including straightening (leveling), altering perspective, or stitching. Whenever a file's geometry is altered, information (sharpness) is lost. This loss can be minimized if a smart resize was done prior to the geometry correction. I've posted an example of the impact on the image here: http://www.paulroark.com/Perfect-Resize-comparison.jpg . PS CC's new up-res capabilities beat Genuine Fractals/Perfect Resize, and it's nice to not have to fire up a separate piece of software.
Paul