Henge Docks looks like a cool company. I bet their mini display and thunderbolt variants will be good performers. 2 reasons I won't buy one; It's massive (though stylish enough I suppose), and I'd like to use some of the other MacBook Pro Retina ports while its "docked". The MBPr built in HDMI port is a really solid performer, and would be nice not to have to feed that signal through the dock. Then again, this thunderbolt hub may in fact work as seamlessly as is hoped, in which case HDMI port access really doesn't matter; Will just use an adapter. I'm a bit of an audiophile, and use the digital optical audio signal from the MBPr's 1/8" audio out port, instead of the analog. It's a nice feature that Henge offers two switchable audio outs on the dock, but I sincerely doubt they incorporate an optical jack, as the MBPr does. Also important to note that Apple's optional external CD/DVD SuperDrive uses proprietary controller hardware to prevent it from being used with other computers (don't ask). As a consequence, it must be plugged directly into a MacBook Pro/Air USB port to function properly. This is a well documented "flaw", and cannot be circumvented without using a different brand or rebuilding the SuperDrive.
Despite the thoughtful incorporation of SIX whole USB ports, and the other requisite ports too, I still like the Belkin ExpressDock option better. I'd like to place the dock on a shelf in my cabinet anyway, not on my desk -- the Henge is just too massive. Undeniable necessity if you really have 3 external monitors though, not just one + an HDTV as in my case. Best of luck to Henge though, I bet there's enough of a professional mobile niche market to satisfy demand for it.