I literally installed Mouse without Borders this week! But hardware is better for secure login screens and the like. So, I still have a KVM switch. One thing I learned is that I don't want seamless mouse between two monitors.
So, I setup "holding" down CTRL which allows the mouse to pass. Its just a nice way to stop accidents and for when I want auto window sizing at borders. This project looks great if it can support holding down CTRL to allow the mouse to pass into the other screen.
I also love clipboard copy. That is kinda a biggie some days.