Quiestion like Wiki vs Sharepoint comes up more often these days
sharepoint is a fancy shared file system with bells and wistles like nice UI, security, publishing through predefined workflow.
Conceptually different way of writing the documentation
wiki is about creating hyper documentation in colaborative way, it's not possible to write a word document with easily navigatable links to other documents that provide more information on the subject, always have to put all relevant information in one file to make it usable. In wiki way short thoughts linked between each other.
sharepoint is liked by people that like to have process in place and like to enforce it.
choosing the right software for wiki makes a big difference.
http://pingability.com
