A great post from Mike Pisani of Local Motors details their experience in selecting a 3D Printer. In the end they chose a Z Corp Z510 and a Z Corp Z800 scanner, both very popular items in the 3D fabbing world. Mike describes the results of the test prints fresh out of the build chamber:
These parts are HIGHLY accurate to the original part/design, even the very fine threads.
Mike's purpose in using the Z510 is to produce prototypes that he can take to a manufacturer. By discussing the specs with the manufacturer using the prototype, he believes the entire process will be greatly sped up and errors reduced. Why not?