I just ordered the second generation of Gnarbox off the Kickstarter site. I am one of those pro video guys that is trying to wean myself off my laptop and this looks like the only really practical way to deal with any sort of quantity of footage.
I also have a 4 TB WD MyPassport drive and while I will continue to use it, once I get the Gnarbox, I expect it will just be used for archiving and restoring projects. It is nowhere near as convenient as a work drive.
Expected delivery is January of next year.
It looks like the WD drives now have this functionality. Is there any advantage left to the Gnarbox?