MSAD Login is a system that connects a Macintosh OS X machine to a Windows server running Active Directory.
If you use your Macintosh in a Windows environment that has a Windows server, MSAD Login can connect to that server allowing you to mount your home drive and get notifications when passwords are about to expire.
MSAD Login's method of logging into a Windows network is very different from the specified method documented by Apple in that accounts are not tied to the server, this means that when you are not connected to the network (e.g. when you are using a PowerBook on the road) you can still log into your local account and access all your files.
Another benefit of MSAD Login is if you accidentally type in the wrong password, you will not be instantly locked out of your Windows account (and your Macintosh), which will help keep network administrators happy and save you the hassle of requesting your account to be unlocked.
The major benefit for network administrators, is that no changes are needed in the Active Directory schema to support the Macintosh account.
When the MSAD Login system is installed, it can also keep the local password in sync with the server, this means that when the password is changed using another computer, you will be informed that the local password needs updating.
When the local password is changed to the same as the network password, the default keychain password is also changed, removing the need to manually set the keychain password (this was previously only available under 10.3).
The system can also use accounts that do not expire, such as administrators accounts.
A useful utility I would pay for would be a replacement for MSUAM on Intel based macs allowing users to change their Windows AD password and receive notification of expired passwords without the need to bind. This utility doesn't do that.
Notifying me that passwords are updated isn't enough.