I just got my device yesterday and I am not very impressed so far. I had the classic "Runtime error" problem, and at least partially fixed it with the 500MB download and copying of the software onto the Mybook.
So now I have the drive mapped under Windows XP and I have WD Quick View running.
What does not work, however, are two things:
1) When I try to install WD Smart Ware by executing "WD SmartWare Setup (x64).msi" from the Mybook directly, I get an error message saying: "The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2753."
2) When I try to connect to the dashboard using the IP address that was assigned to the Mybook, IE gives me the message that "Internet Explorer cannot display the webpage". Connecting to my router's web interface, for example, however, works fine.