The only real benefit I see from watching the vid (having never actually used one myself, mind you) would be ease of plate loading. You'd be restricted to the plane of motion of the carriage itself, but that doesn't necessarily mean it would differ much from a standard bar.
What the hell...I say give it a try and see how you like it.
The parallel handles are a nice feature, but yeah, the restricted ROM can be a pain in the ass for a lot of people. Also, like Leg Presses, I know dudes who know how to "work the machine" and end up lifting ridiculous amounts of weight that they couldn't even touch by 1/2 on a barbell.
There are a few companies making DL machines. The one in the video appears to be the current model made by Hammer Strengh (actually Life Fitness these days). It is not good. The handles, though parallel, are at an awkward angle, and very uncomfortable.
Better off with a Trap Bar. Here is what I think is the best one around (scroll down and look for the Dead-lift / Trap-Bar).
A better machine version than the one in the video, is this one.
Deadlifts are an awesome exercise. If you are not a power-lifter, than I feel a trap-bar or machine version is fine.