I use TortoiseGit on Windows because working with hundreds of repos via the file browser seems more natural to me. Standalone git clients cause too much friction when working with lots of repos in my opinion. They get cluttered with a huge list of repos that I have to organize separately from how they are already organized on my file-system.
With TortoiseGit, when I find a git repo in the file-system and want to start working with it, I don't have to start another program, I can just activate the file browser's context menu with a single keystroke and then I can instantly see all of the Git commands that I normally use. I hardly even have to look at the list of commands though because the next keystroke is usually to hit the letter of the command that I want: (M)erge, (C)ommit, S(w)itch/Checkout, (L)og, etc... because you can customize the context menu to show the most useful commands.
(Disabling overlay icons in TortoiseGit is also a good idea. I typically just delete their registry entries via SysInternals/Autoruns.)
I have recently tried Tower and it provides similar functionality without the performance issues.