You should also give Sublime Merge a go. I'm mostly a CLI git user, but Sublime Merge is so lightweight (and intuitive to someone who knows git), it's had me using it quite a bit.

I haven't really used any of the other clients long enough to give you a solid answer.

For me, Fork just works, I can scroll through the commits easily, file trees are available as a tab for each commit. The UI is very easy to use and discoverable, that's why I like it.