There is a very long list of enhancements between these releases, including bug fixed and stability improvements.
New modules and enhancements (JDE, ADF support)
Capture screenshots options
Support for newer browser versions
Test execution / Test set in OTM
Export project in OTM
Linux platform support for OTM
If you download the documentation you should find the release notes inside containing the what's new section. Unfortunately, only 12.2 and 12.1 are available on the DL site.
Link to the docs (not available online, need to be dl)
Normally, OS supports EBS 11i. Crahs might due to browser profiles issues. Which browser do you use?