I use MS Office - would you recommend iWork over Office?
I have both and the only reason is some of the stuff i do for work can only be done using MS Powerpoint. 99% of the time i use iWork and just export to a Windows friendly version.
Keynote wipes the floor with powerpoint, Pages is just as good as word, Numbers isn't quite as good as excel but from what i have heard the next overhaul of iWork will include a big improvement to Pages & Numbers to bring in line with if not better than Word/Excel. Keynote will also be updated to keep it ahead of the curve