I have one of these for my Win XP and Linux boxes, and am completely happy with it. But two words of warning:
1) You switch between the boxes by hitting left Ctrl key twice, it may be a problem in some situations, i.e. you use that key while playing games;
2) If you have an old style AT keyboard and use an PS2 adaptor it may not work properly and you will have to snip one of the pins, therefore voiding your warranty. However in my case it worked fine without any midifications.
Just a word of advise.