We have one of these at our school! :)
Not much difference to a good quality laser cutter etc (well ish :D)
Did a fair bit with zcorp machines at uni, the main cost (well imo) is the price per sq. in. $3 an inch, may not sound much, but think even a 5*5*5 item you're talking nearly $400.
I dont think it was cheap at the time, its quite an old bit of kit I think now...Its definetly not as saphisticated as the one in the video....It uses white powder though, very good it of kit, we also have a laser cutter, that is impressive!
and now there is one that prints in chocolate
BBC News - Printer produces personalised 3D chocolate
We have one at our school too, being a technology college (at the time when we got it). It cost about £26k I believe, and is now being run as a radiator as DT can't afford to run it. I think a fan went once and the supplier tried to charge £120 to replace it - the DT tech bought a normal case fan for a computer for a few bob and that did the trick.