When MS Office 2007 came out everybody started receiving xlsx and docx files and the old versions of MS Office most folks had installed couldn't open them. For the die hards (there were a few) I installed the compatibility pack (buried in the bowels of Microsoft's site since I guess they figure most places are willing to just throw money out the Windows(tm) and will buy a new version but I see no reason to re-buy something as trivial as a word processing program which works perfectly well already), but lots of folks got Oo instead. I even changed the icons for some of them to "ease the transition" and to tell you the truth, a lot of them didn't notice the difference. Some that did liked the presentation program better than Powerpoint and swung the whole sales staff over just on that reason. When users ran into something that worked differently (like how to edit headers/footers or tracking changes) they just chalked it up to the "new version". Since we already use Firefox and Thunderbird some folks have migrated over to Ubuntu from Windows (I always used a LTS version but then found they had decided to upgrade to the bleeding edge on their own later and seemed to have no issues most of the time so I let them play). We're not a big company (maybe 100 PCs), and we do engineering and development work so most people are pretty tech savvy, but of course the big issue was our ERP system which is designed for Windows, but its turned out easier to maintain that through terminal services anyway.