FIM directory sync vs scripts

Hi

I'd like to get some feedback from those who have used this product before. We are investigating synchronising from 5 authoritative ADDS instances to a single AD LDS instance. I have demo'ed FIM and see some value in how it handles duplicates, reporting and so on. What we are after is simply a common LDAP directory that we can point applications to for basic contact information.

Now FIM comes at a cost of around 18USD per CAL which isn't extortionate but also not cheap.  For you experts out there, what are some of the reasons one would motivate for using a tool like this versus ADSI scripts?