Full Disclosure: I'm a backer, though not early enough to get an early-bird unit.
I look forward to trying this tech when I finally get mine. I have lots of reservations, but am still happy with my decision. I'm glad they seem to have found a way to paste/reflow boards that are inked. During the Kickstarter is was going to either be able to lay down ink, or paste/reflow. I.e., you could only paste/reflow a traditionally fabbed copper board, not a prototyped ink board that was fabbed by the Voltera. That was a pretty serious limitation, making the unit somewhat bipolar: you could quickly prototype boards in ink but then had to deal with soldering yourself. Once you were more confident with the design to send out for traditional copper boards, it became a nice alternative to stencils and ovens
I can't speak to the resistance issue, but in my mind the other huge limiter is the feature resolution limit. Sure, there's a bunch of things you can prototype within the limits of the Voltera, but you don't have to move much beyond Arduino-class designs to bump against the ceiling. Things like the Intel Edison connector is way out of reach for this thing, and even a DIMM connector (think Raspberry Pi Compute Module) is too dense. They will have some breakout boards for common footprints that are too tight, but that's a half-measure in my book and only adds to the number of things that have to get redesigned on the path from a Voltera prototype to a real board.
In the meantime I went ahead and bought an OtherMill, which can handle much smaller feature sizes, and uses traditional copper-clad boards. You have to connect your own vias, but it will at least drill them for you. And getting the alignment between both sides of the board can be tricky. But I've already done some interesting prototypes with that board, including stencils, and now have a toaster-oven-based reflow box. Had I known about the OtherMill I may not have sprung for the Voltera. Hopefully they complement each other---even if the Voltera becomes mostly a solder dispenser that's a win over what I'm dealing with now.