They are 'standard' laptop keyboards, but I get the impression that Apple spent a lot of time and effort getting the materials and the lever designs just right. The key travel, pressure needed and so on are just perfect!
As well as that, the Mac keyboards seem to be considerably quieter than PC counterparts, from my experience.
A lot of people wouldn't really consider the keyboard when it comes to a premium computer experience, but it really does add towards the high-quality nature of Mac notebooks.
EDIT: I forgot to mention that the MacBook Pro with Retina display seems to have a shorter keyboard (vertically) than the last-generation design, obviously because the entire casing has been thinned. It took a little getting used to (felt strange coming from my old, heavily-used MacBook Pro), but it feels even nicer to type on somehow.