So which version to choose from?
12.1.2 is out for a while, so a nice list of fixes exists already.
12.1.3 is new on the block from August 2010 on. Going for this version brings you to the latest and finest verion of the eBusiness Suite. And will fix some previous bugs. And will introduce some new bugs.
To make things a little more complicated, Metalink states:
"R12.HR_PF.B.Delta.3 (9114911) - Oracle HRMS RUP 3: This is the lowest level of HRMS Release Update Pack (RUP) on which Netherlands Payroll customers are supported for 2010/11 Year End processing and statutory updates effective from 01-Jan-2011."
And this Rup 3 is already included in the 12.1.3 version, but is an extra Rup to install on top of 12.1.2.
I gonna propose 12.1.3. Either way we will have issues to fix, so it seems better to fix them in the latest version. As such, the customer is one relaese point higher, and support can not ask you to upgrade to 12.1.3.