There have been several reports of issues with Redactor 2 and MIGX. These were:
Several z-index related issues that made dropdowns and popups disappear under the MIGX modal window. This also affected other components, like FAQ Manager, basically anything that loads Redactor in a modal. This has been fixed in Redactor 2.0.1, which will be out soon.
Issues with certain features not working in MIGX windows, including the resource typeahead, Eureka browser, and html/syntax editor. This is due to hardcoded instantiation logic in MIGX that was not updated to the new code in Redactor 2. For this we’ve just sent a pull request to Bruno to take out that hardcoded logic, and instead making it use the standard MODx.loadRTE. This pull request can be found here.