Yes, I just picked up git for Windows, and it is atrociously unusable. Brutally atrocious. It's not like Windows is a popular operating system - git shouldn't support it as a first-class citizen. ;)
I've been using the whatever default Windows port that is linked from Git's download page for several months bow and there is nothing atrocious about it. It works well and it does differ much from the Linux version. (edit) The command line version that is.
git gui works wells for me on Windows with msysgit. It's ugly, and there are a good number of small issues, but it definitely provides a reasonable user experience.
And of course, the command line option through msysgit is great.
Since the target group were designers, the presenter used a Mac, and tried to do everything using a GUI client for Git.
I don't remember which one he used, but it ran natively on the Mac and it looked quite nice.
(Still, the presenter sometimes struggled with that GUI. He was obviously more used to the command line.)
Most git actions don't need a deep understanding of Git nor a full GUI to function. I think git gui and gitx probably are enough to get a designer going.
I use Git, and its a wonderful piece of software craft indeed, but it does not have Windows/Mac clients, that designers often use, as their base OS.
A decent usable frontend for Git, on platforms other than Linux too, needs to be developed, for it to be usable by designers.
Edit - I meant to say officially supported frontend and support for other oses by git.