The editor is still very, very limited in Safari / Firefox. You, by far do not have the same interface as you would have in IE6/7. But it.. works? That's more than you can say about 4.61 ;-) My recommendation is to perhaps get your clients to upgrade to an Intel Mac and perhaps use Parallels for Windows virtualisation. We have done that for a couple of clients and they are more than happy. I'm also on an Intel Mac, developing EPiServer solutions in this environment.

It works on Firefox for Windows I can confirm that, but without Rich Text Editor. Thank you for the answer

It is possible to change the editor in EPiServer CMS 5 in order to make the Edit mode of EPiServer work in other browsers than IE. A good article describing this is posted at http://www.episerver.com/en/EPiServer_Knowledge_Center/Download2/Code-Samples/2646/Editor-for-non-IE-browsers.

Hi! A detailed list of all functionality that is not currently supported for Firefox can be found in the "Not Supported in this Release" section of the release notes for EPiServer CMS 5 R1: http://www.episerver.com/en/EPiServer_Knowledge_Center/Documentation/Release-Notes---EPiServer-CMS-51/#Not%20Supported%20in%20this%20Release