I "scratched an itch" recently with my personal Oracle E-Business development environment: cleaned everything out, chucked CentOS for Oracle Linux 5.5, and installed EBS 12.1.3 on and 220.127.116.11 database.
I'm finding I really like EBS 12.1.3. Let me share a few reasons:
The improved User Experience (UX).
The type-ahead search feature has been a long time coming and makes a huge difference all by itself. But wait...there's more! Read more about it here.
The Smoother Install
Surprise! Rather than creating from scratch, I used Oracle's VM templates (part of the reason I swapped CentOS for Oracle Linux). You can check them out here and here. I have yet to try out the Sparse Middle Tier template, but I may go through another round of rip-and-replace just to give it a go (yeah, another itch I may have to scratch).
Iterative Improvements in Oracle Projects
Having "cut my teeth" in Oracle Projects, I'm always on the hunt for improvements in this particular product suite. Well, there's a bunch that come with 12.1.3. You can find a pretty good overview (summarized from Oracle's 12.1.3 RCD) here.
Reading all the references I've pointed out here made me itch to move to EBS 12.1.3. Check out the references here and let me know if you need to scratch your own itch.