Having to maintain the apps in two operating systems could be an issue. If we are talking about the training of the UI, I think a staff member of IT could put together a presentation and have people introduced to it before getting a pc loaded with it. Everyone knows how to use a mouse and keyboard. It is a matter of where everything is now located and how to get around in the interface. A few hours or day of time spent putting together a good presentation once could help introduce the os.