Family Tree Builder is now available for Mac! It's free to download, easy to use and includes all of the main features of the windows version.
Once installed, the software will run directly on Mac computers. The minimum OS version supported is OS X. It uses a system for porting Windows software to Mac called CrossOver by CodeWeavers.
For more information, including Mac installation procedures, see the MyHeritage post: http://blog.myheritage.com/2015/01/family-tree-builder-now-available-for-mac/