In Sten Vesterli’s post the question the question of whether one should go for JDev 11.1.2 or JDev 220.127.116.11 (lastest R1).
Chris Muir answers this in the comments: 11.1.2 is for JSF 2.0 only. In 11.1.2 the bug-fixes will be back-ported from 18.104.22.168 as this is the version Oracle is using for their Fusion Applications development effort.
On the Oracle Forums I found another discussion about this. With a great answer to the question (this one by Frank Nimphius from Oracle):
the question is what your motivation is to move to JDeveloper 11.1.2? JDeveloper 11.1.2 is an intermediary release for developers who want to use JSF 2 for their UI building and leverage new features. The successor of JDeveloper 11gR2 is 12c, which will have the full SOA stack. So if there is no business reason to upgrade to 11gR2 and if the application is in production, I would prefer upgrading to 22.214.171.124 and then to 12c instead of moving to 11g R2. So the motivation you have determines whether your idea is a good one or not
This post was written before ADF Essentials was released. Today JDeveloper 126.96.36.199 is the IDE to use with ADF Essentials. 12c is out but at the time of writing (2013-10-20) is not yet stable enough for production environments.