OpenOffice works well with the Mac, the PC, Linux, and so on. It works so well with Microsoft Office that you can easily share documents with folks that don't use OpenOffice; no hassles at all. Fully-featured, versatile, powerful Office Suite.
J. Birnholtz, C. Gutwin, and K. Hawkey. GROUP '07: Proceedings of the 2007 international ACM conference on Conference on supporting group work, page 51--60. New York, NY, USA, ACM, (2007)