Although things are a little more hidden in the UI for stuff that was upfront in git-tower, all the functionality I needed was there. Before committing I noticed sourcetree had a bunch of updates including a major one that seriously boosted performance on my large projects and the bug on appending was fixed. I would have paid the $79 to buy it but that was in USA dollars and I felt that was too high in my currency when developers in my country generally make 1/2 of developers in the USA. git-tower was fast and was a little easier to use (for example automatic stashing) and things in the UI were worded a little more intuitively. I was just too frustrated this time so I moved to a trial of git-tower. Sourcetree is a free, easy to use Git client for both Windows and Mac users that is built by Atlassian, the same company that owns the hugely popular bug. A short while ago it got really slow and it would mess things up just trying to do a simple append to the last commit (on a project where I am the only person submitting). SmartGit has the same intuitive user interface on Windows, macOS and Linux: graphical merge and commit history. If you want it for git-difftool as well: git config -global diff.tool opendiff.
You could instruct Git to use it automatically for git-mergetool with: git config -global merge.tool opendiff. However it was still very useable when it was slow except on my largest projects but I could fall back to the command line if needed. SmartGit assists Git newbies as well as it makes experienced developers more productive. It is a command line tool which opens the GUI of FileMerge. If you feel that you need an extra tool to manage your repository, because none of the other options makes you feel comfortable, GitKraken could be the answer.
GIT GUI TOOLS FOR MAC UPDATE
Sourcetree seems to have a history of working great, getting an update and then performing really slow until another update. For basic things the command line is fine but I'm finding more and more I like the visual representation of what has changed offered in sourcetree and git-tower. Jason's Experience Used command line, git-tower and sourcetree.