Its battery isn't replacable: I know the iPad has respectable battery life, but if you ever have to work on a long plane ride and in a café with no available power outlets, you need excellent battery life and a back-up cell that is easy to install. This isn't possible on either model of iPad. As on all other Apple mobile devices, the battery is sealed and nonreplaceable.
WHO FUCKING CARES? By the time the battery is dead, you'll have moved on to the next iPad or the next MacBook Pro, and even if it does die before you do switch, it's not that expensive to replace it.