The beauty of magit is that the ui is just text, so you can navigate through the entire interface using just your keyboard without "shortcuts". Selecting lines to stage is just selecting lines in the diff like you'd select lines in the editing buffer. Its really nice and caters to power users, I don't know of anything else like it.

Probably to be read as (very good) (editor integration) rather than (very good editor) integration.

Yes that's what I meant. Thanks :)

Then it would presumably have been a feature of Sublime Text, rather than a standalone application?

Well, when I say "integrated with ST", I mean they will be integrated with each other.

That way, I can be a power user of Sublime Merge while only using ST occasionally (because I'm more of a vim user), or vice versa (because I'm more of a magit user). Or you can be a power user of both.

I think it makes sense in this case to have two applications. I personally am an avid user of ST, but I generally prefer the command line for git. However, there are some things that it's nice to have a GUI for when git'ing, so this is ideal for me.