Microsoft responds after the recent Apple announcement arguing that iWorks is not software for serious work. I suppose, but I would suggest that Word is kind of a tweener – not really necessary for writing and not robust enough for page layout or serious epub configuration.
I see iWork as more of a competitor for Google docs. I pretty much write for a living (with Google docs) and for me I would need to be convinced to move away from docs.
I do prefer a keyboard and I am certain this is the case for those of us generating long form content. It can be handy to do minor edits on a tablet and it is certainly handy to be able to work on a document from multiple devices, but a keyboard still is necessary for easy input. I see devices as complimentary rather than as alternatives. Most of us who use devices for work have probably now gone to some combination of devices so this either/or argument is not valid.
iWork is interesting because it is free and allows collaboration. Why would anyone in a school setting spend money for writing software? Use Google docs or iWork Pages.