The first beta will see the light in a few days from now. The version in the screenshots is functional and I took the screenshots during the testing. Initially, it will be somewhat stripped and not have all functions that you can see in the Windows Viewer. However, once the Beta 1 is out we'll be gradually adding more features in the following few months. In the end the final Viewer for Mac is going to have virtually same functionality as the Windows Viewer.
When we release Beta 1 we will provide a list of features that we will be including so that you have a better idea of what the final release will be.
In addition, Viewer for Linux will also be released and mirror the functionality of the Viewer for Mac.
Of course, Host/Agent for Mac is among our highest priorities. We plan to release it this year, but, unfortunately, we cannot provide a more specific ETA on it yet. However, we will certainly notify all our users when Host/Agent for Mac is released.