It's a great-looking gadget, but where possible I'm still going with a laptop and a separate image storage device for redundancy, not two disks in the same device.
See, there was this short in the wiring of the hosteria in El Calafante I was in, and the fuse on my laptop made the most elegant sizzling sound. It was fortunate the other backup device wasn't plugged in at the time, the short took out lots of electronics over three buildings. (And moreover, it was "fortunate" that I took the time then to figure out how, after having lost power on the first device, I was going to continue to have two separate copies of images I made during the rest of the time.)
Still, if I *couldn't* bring a laptop...
Joe