Here is a review of 14 word processors including 3 online alternatives.
The author's (Zaine Ridling) summary:
my only advice is to look beyond any one word processor and seek openness in your choice of file format. Do not allow yourself and your data to be locked-in to the whim of any one vendor. ODF can be used by any word processor if the vendor so chooses, and it satisfies the criteria outlined by Sam Hiser of: "(1) being developed and maintained in an open, multi-vendor, multi-stakeholder process that protects against control by a single organization; (2) being the only openly-available standard, published fully in a document that is freely available and easy to comprehend; (3) being the only format unencumbered by intellectual property rights (IPR) restrictions on its use in other software, as certified by the Software Freedom Law Center; and (4) offering interoperability with ODF-compliant applications on the common operating system platforms of Windows, GNU/Linux, and OS X, along with most online word processing apps."
For me, I am still using Word 98 (on my XP laptop) and Google Doc for online sharing with collaborators. Reason: Inertia of change.