I went down this road, and it works surprisingly well. If you're trialling different solution for writing technical developer documentation, see a more precise description of the workflow that I pushed on my blog yesterday: http://kray.me/pro/doclegit-git-documentation-server/ (sorry for the copy quality, english not my first langage, corrections by mail are welcomed)
While the software developers are comfortable learning and using Markdown or other markup syntaxes, I eventually would like to spread this approach to other technical people in the company. In previous attempts at teaching basic scripting (Awk, Ruby, Python) to engineers who are comfortable writing complex logic operations in Excel and who can dabble in VBA - I found a lot of resistance to the idea of learning a new syntax. So I expect the evangelism required to get these colleagues to write in Markdown will be greater than showing them Lyx, which at least looks like one of the editing modes in Word.