[dreamcompiler]

Magit is designed for people who are already used to the git command line. Sourcetree is not.

Sourcetree is mouse-oriented, and to me it has the same disadvantages as all git GUI clients: I'm never quite sure what it's doing behind the scenes, and it cannot quite do everything useful that command line git can do.

Magit is keyboard-centric like emacs. Yes, so is the command line but Magit relies on individual keystrokes rather than typing in a line of commands and hitting <return>. The result is that once you get used to Magit you can fly through git operations and it's almost always quite clear what git operations Magit is doing. There are still a few exotic command line git operations Magit won't do but I almost never need them.