People who use commit -a terrify me. The value of a tool like this is it makes it trivial to review changes, stashes, etc. in a convenient way without needing to look up commands. This tool in particular is built to handle huge repos which most other front ends straight up can't. And it does it with a 1mb binary and almost no ram.
git add -p is my default. Usually what I have been up to belongs in 2-3 separate commits, each with a good commit message. For example a bug found and fixed while developing a feature always goes in its own commit.
