G'Day Mr Tuck, here are some bennefits according to MS:
-Automatic OLAP cube scheduling
-Define timesheet views in Project Web Access
-Delete resources in Project Web Access
-Lock down actual work in Project Professional
-Protect Actual work in Project Web Access
-Project Manager self check-in in Project Web Access
-Timesheet lock downs in Project Web Access
From our experience, '03 does not solve all problems as
was anticipated (i.e. all the defects that we were told by
MS support that would be fixed were not all fixed).
From personal readings, I do feel it is worth it to go
to '03 for the simple benefits identified above,
particularly for the "lock down actual work in project"
which simply put allows the system administrator to lock
down actual work to prevent others from editing it after
the specified time period has passed.
This is a terrible gap in '02 which my auditors did not
like too much ;-) and they gave us heck for it. Enjoy!