Git Extensions has certain shortcomings (search doesn't work that great, deleting branches is clunky etc.), but its competitors - on Windows at least - are even worse, I agree.

Besides, Git Extensions is written in C# and open-source... once I finally have some time on my hands (read: never), I'd gladly add some simple features that I'm missing in it

I really like Git Extensions commit screen, the best from the git GUIs I've used. It has great shortcuts to stage/unstage/reset and you can even separate lines to be commited.