The problem for me was that the a belkin dock requires me to use the one available thunderbolt port for my video and I would rather use it for an external thunderbolt SSD that also has a passthrough. Finding a reasonably priced thunderbolt monitor with passthrough is pretty much impossible. I only care about my current machine not a theoretical future one.
The Caldigit doc has been rock-solid for the last 3 months. I run a virtual windows machine in Parallels using an external thunderbolt SSD drive and it is awesome. The only FW I have used was a thunderbolt to FW adaptor to move files off of a FW drive to a USB 3.0 drive and it worked fine. For me the Caldigit docks HDMI port for video was much more useful than a FW port.
Did you rule out the source USB output? How many XDA-1s did you listen too to come to the conclusion that it is an XDA-1 problem and not a problem with your XDA-1? How did you rule out a cable issue? I'm sure your post would have been lauded on Head-Fi but you simply do not walk into Head-Case with that kind of shit.