Of course, since it is from Microsoft, it is Windows-only, but that is fine for me. This also isn't the first product like this, but it is by far the easiest. Synergy creates a competing product, but apparently the setup is complicated enough that people have to make guides for it. MWOB is easy enough that no instructions are needed beyond what it gives you in the installation.
My only complaint so far is that it doesn't support vertical screen stacking, so right now I have to mouse out to the right or left to get to a monitor that is actually above, but that is fine by me. It is understandable, since I don't think tons of people have vertical dual monitors lol.
Anyway, if you have 2 separate computers hooked up at your desk, check it out. It has made my life so much easier