Sublime Text
This software is an alternative to Atom. In fact, Atom is based on it. You might like to follow a guide on setting it up for use with Git and so on, there are plenty out there. It's OK if you use either of these in class, as well as command-line only of course.
It has some nice additional features, and for me, a nicer user experience, but YMMV. I'm describing it here because it supports the ability to checkout git tags, something mentioned in our wiki.
The main reason I don't like using it is that it isn't 100% free/open source. Users are asked to pay, but they have an unlimited free trial with all features enabled, so most never do. I prefer Sublime, but it is neither free as in speech or free as in beer. It also has few developers, giving it a bad bus factor---though most university research has a lower factor still. However, it is a very good tool, and you can use the trial period for years before you feel guilty and pay. Also, Atom is GitHub, GitHub is Microsoft, Microsoft is Microsoft, so pick your poison I suppose (or learn vim like a real hacker!)