In general, we like things with which we are familiar. This is the basis for brand identification that is one of the guiding force in marketing. This applies not only to users, but to administrators, as well. Although I am not saying to trick either users or administrators into thinking that they are using NT, there are number of things you can do to ease the transition. An important aspect is the appearance.
Many users shy aware from Linux because it looks different.
Because each of the different windows manager has a different way in which you interact, how familiar you are with that interface defines how well you can work with it, which in turn defines how comfortable you are with it. The solution is to provide a window manager that is more familiar for the user. One alternative is the KDE or Gnome, configured as the default window manager by SuSE and RedHat, respectively. Both provide a similar look and feel to Windows. Although they are similar, there are enough difference to throw people off.