Wut. A unibody mac is generally much easier to take apart than most PC laptops; the shell has one metal lid held down by a handful of precision screws, instead of 15 plastic hatches covering separate components and eleventy screws. You remove the lid, everything is exposed, nice and tidy. You can upgrade your RAM, switch out your harddrive, and have your laptop screwed back together again inside of five minutes.
Couldn't be simpler.
This.
I've updated RAM and hard drives in many many laptops and the unibodies are much easier to work on then snapping keyboards out, etc. You can fault the battery issue, but, in general, the oddly shaped internal batteries are one of the reasons their laptops last longer off AC.