It works on Mac just like in the screenshots. If it doesn't have a "Revert" button it means it couldn't find any old updates to revert to. You can look in the updates folder mentioned above and see what is there.

Let's continue discussion about 1.8 in this new thread:
viewtopic.php?f=3&t=2180
There I provide information on how to get your download link, how the new launcher works, how to go back to 1.7.12 if you need to, etc.