Should I migrate from Django 1.2.5 to 1.3.x ?  Are there any undocumented issues?
Migrating to a new version of Django (especially from a directly previous release) is really easy and takes less than ten minutes for one project (if its not super complex).
It it's running for 18 to 24 months I would better upgrade. After one or two more releases of Django (one major release each year) they will simply not support security updates for older versions anymore. To be be save you can make the step to 1.3 and then don't need to upgrade further, except your project is running even longer.
Short Question
Are there any compelling reasons to update Django 1.2.5 to 1.3?  If the noted changes in the release notes do not impact my application directly.
EDIT:
To better clarify my question (thanks S.Lott!): Are there any issues not mentioned in the Django 1.3's release notes that I should be aware of if upgrading from version 1.2.5?
Background
I have done all of my development on 1.2.5 with no troubles.  I will be deploying my application within the next week or two and it's life cycle will be 18 - 24 months of constant use.  
Secondary (more general question)
Just  prior to a release, is it good practice to get the latest and greatest (stable) version of your dependencies?