I don't work on windows anymore, but Git Extensions is still my favourite Git Gui

https://code.google.com/p/gitextensions/

This. My favorites are the (un)staging by hunks/lines and 'use rebase instead of merge ...' option.

Did you try Tower? That's a paid app though.

I personally use the command line but a lot of my team members aren't comfortable with CLIs so that's why I was exploring Sourcetree and found it to be quite full-featured compared to others I've tried. I've found that Git has so many options, most GUIs barely scratch the surface of what is available.

Thanks for the suggestion though. I'll give Tower a whirl.

50 euros + the price of a Mac :-D