See What's New in this Version? for a list of the things that we have added.
The main difference is that the File Manager does not have Audio or Portable Devices views. However, it does search the entire computer, not just specified folders.
ANv2.8 Mac does not support Output Recording, Presentation Capture or Screen Capture, as well as some of the other new functionality added in ANv3.0 Windows.
Other differences are: ANv2.8 Mac does not support footswitches; uses the Mac spelling checker and other text tools; supports exporting to iTunes but not to a generic Album format.
With version 2.7 we have introduced a new encoding system; we now record using the standardised Opus audio encoding system. This means that your files can be played on both Mac and Windows platforms. If you are working with older Mac files and want to be sure that your Mac .ran file can be played on Windows, you can convert its audio format in File>Properties.