Actually, the migration is a lot easier. for one one the older machines you can still retain all your ald settings and OS. You would have to upgrade all 9.x machines to at least 9.22 to maintain this compatibility.
Problems1. OS X 10.2 is actually a different OS not an upgrade. All, and I mean
all programs will have to be reinstalled with OS X compatible programs.
2. Will probably have to get to your printer manufacturers website to find if you have printer drivers for any of your printers. Older drivers will not work.
3. Many of your network and privilage settings are more robust in OS X, however the old option of having shared folders is lost, you will have a series of public folders for each user. Not as friendly as the old system.

I am still trying to find a work around, so if you do find one please inform me.
WindowsLogging into the windows domin system is easy. As long as your windows machine allows one to log in, you will from OS X. Dont even need anything special. It uses
Samba for this. You'll probably need to install it, but thats all. Just make sure each user on the machine has permission to log in from windows if you want them to log in from windws. Can be set at your system preferences.
OthersAll your users will complain at first. No control panels, fonts hard to find, no previlages to certain places.
And where is the f***ing chooser? With more use, they will like it.
Just remember to get OS X native versions of all your programs and drivers then you'll probably not have any problems.
;( Check at apple (
www.apple.com) for a list of compatible computers. some of the older ones will not load OS X, and some others will require a BIOS update.