I wouldent actually say theres much difference especially if your going from unlimited to PLE (which is maya complete) as you doent get the ncloth system and you loose the unlimited functions (cloth, fluids, fur, hair etc)

YOu do gain a few tools, bridge being one, insert edge loops etcetc, and the UV mapping has some cool little tricks to see problem areas.

Oh and the interface has changed a bit, if you look in the whats new section of the help file that should help you out a bit.