Git is a great tool. The Windows implementation msysgit makes me unhappy: It is extremely slow on my machine, and if you search on the web, this is not an uncommon problem. Usually I use egit directly from Eclipse, however in one project I have to use git-svn and want more control over whats going on from the command line. (see update below)
But git kills my turnaround time. I found a somewhat bloated, but fast solution: I have a Linux-virtual machine (Ubuntu) that mounts my git directory as a shared directory. Now I am using the Linux shell in the vm. That is actually much faster than the windows git command line.
So if you are suffering from a slow Windows git, you might want to try this approach.
It seem that the reasons for a slow msysgit are manyfold. I was able to fix it somewhat by commenting out the dynamic prompt in /etc/profile
#Comment the lines below
However, git svn rebase is still faster in my VM.