There is, for me, one downside. I hate the F-Lock key with a passion. It turns the F keys into stupid M$ buttons when it is toggled on. For me, as a Linux developer, this means that my hotkeys start doing crazy stuff whenever I bump the F-Lock key. I really should get around to popping it off the keyboard.
Other than that, it is a good solid keyboard. I work on this thing for around 10-14 hours a day, and it has been pretty easy on my wrists.