In March 2011, we tested the content-authoring interface within SilverStripe CMS against various major browsers, in order to provide recommendations to our users, and to identify opportunities for improvement.
The testing covered how both performance and functionality within the CMS worked.
To sum up our testing, IE7, IE8, IE9, and FireFox 4 all work well from a functionality perspective. IE7 was slower so we recommend users of IE7 upgrade to IE9 or Firefox 4.
Since we had a limited amout of resource available for this project, IE6, Safari, and Chrome were not tested, as they are only used by a small percentage of SilverStripe users. We would be very happy to include test results from the community in the future.
For a more indepth view into our findings, please download the SilverStripe CMS browser testing overview (PDF, 115kb), which contains much more information on our methodology and conclusions.