DonationCoder.com has a very good Word Processor Review by Zaine Ridling, divided into three tiers: Major Word Processors (Open Office, Office 2007, Word Perfect), Second Tier Word Processors (AbiWord, EIOffice, etc.) and Online Word Processors (Google Docs, etc.) that is well worth reading for an idea of the capabilities of each. The final Pro and Con tables are handy.
The predictable quibble I have is that the reviewer apparently believes that application features are disconnected from save formats. So while he opens with If ever a maxim fit, one size does not fit all applies accurately to word processors and diligently mentions the different feature sets of the different applications, these different features never need to save any information that ODF cannot handle, it seems.
I think the best resolutions is that if a document does use some features that a format cannot handle, the application should alert the user who can choose the appropriate format. For Office 2010, for example, a user could set ODF to be the default default, and OpenXML can be the fidelity default, for example. I think that is one good way to reconcile the basic ODF-wasn’t-designed-for-our-feature-set issue with the we-want-ODF-as-our-default-format issue. Rather than panicking ‘It is impossible to use ODF because it doesn’t support all these things” (which is clearly true for many, but hopefully not for most Office documents, presumably following one of the standard statistical patterns) on the one hand, or chanting “ODF gives you everything you need” on the other hand (which similarly is hopefully true for most, but certainly not all Office documents)
It would be interesting to also include the word processors from Adobe (FrameMaker), IBM and Lotus as well. And it would be interesting to also include validation reports where the XML-in-ZIP save formats were validated against their standard schemas, since validity is a great tool for determining whether an application is doing the right thing,