Here’s the difference between the two Canon lenses:
“Rokinon model AE14M-C is Rokinon’ s newest version of its most popular 14mm F/2.8 Ultra Wide Angle Lens for Canon. It features all of the same specifications of Rokinon model FE14M-C but also has a built-in AE for auto metering with your camera. This allows your camera to automatically select the correct apertures and exposures.”
Decent review at photozone.de:
Performs pretty well for the price, the main limitation being geometric distortion that would be a concern mostly for architectural photography.