I'd actually consider iPad 2. I have an android tablet and iPad gen 1. Ipad hands down has the most Apps for writers. Mind maps, index cards that will sync with scrivener,( awesone for writers) note taker HD for hand writing down your thoughts, translation dictionaries.. (I used this when one of my characters spoke broken french), Pages, Chapters, just tons of software aimed at writers.
For writers I just think from using both, at the moment, iPad has a lot more to offer.
Take a look at
these articles for more ideas..
HERE and
Here
Edit: Pages is also compatible with Word docs. In writing its not just about the office software but all the other tools as well, although Android does have some, it doesn't match iPad yet.
If he was shooting for Windows 7, One note can't be beat.