Most of the USB3 docks do indeed need to load up the Windows device driver before they start working, so you can't use the dock at the BIOS screen for example.

Mine works fine *at* the login screen, though (I don't have to log in before it starts working), and it works 100 percent of the time, it's never given me the kind of troubles that your client experienced with that other brand.

My only complaint is that it's not a true "dock" because I still have to plug in a power cable separately. So that's two things I have to plug in when I dock it instead of one.