I know how to setup araxis merge to be my git diff / merge tool, so if I do git difftool it automatically launches araxis merge.
However if I do git difftool upstream/master (to see all the differences between current branch and upstream/master), it launches the app one by one for every single file that is different. Is there a way of setting it up so I can get a folder comparison type view, and then go down and view each file diff as I choose? i.e. similar to this http://www.araxis.com/merge_mac/overview2.html
The only way I've found to do this is to clone my repo into a new folder, switch to the branch there, and then do a normal araxis merge folder comparison.
I don't know if this is still interesting for you but recent versions of Araxis provide direct access to Git repos:
http://www.araxis.com/merge/topic_plugin_git.html
So, if you want to launch Araxis to compare your master to origin/master, you shall be able to do it using
git log -1 origin/master
to obtain the latest commit in origin/master (say 123456ab. Then, open Araxis and use your working copy folder as one side of the comparison (/path/to/repo). The other side shall be set to
git:///path/to/repo#123456ab
Then, Araxis will compare your WC to origin/master.