Depends on what you want to do with the documents.
For sharing around (including submitting editable docs to faculty) Office is probably better.
If your documents are for yourself or going straight to print or PDFs then iWorks may be better. If your faculty will accept PDFs... then you may not need Office. If you collaborate a lot, then you probably do. If you need fancy schmancy footnotes then you need to do some more research.
Office has more features... but if you aren't using those features they can get in the way. iWorks has most features that most people need, and it's better at making your documents look good.
For more details, you should read one of the other 900+ threads that already exist.....