they look like they do great work as well but if you intend to paint the models after printing beware of the Invision HR machine. It uses a wax based support material that makes paint not want to stick to the model. Also, the Objet & Envisiontec machines are much better resolution.
example:
Invision HR spec’d @ 656x656dpi in X&Y & 800dpi in Z layer thickness
Objet Eden spec’d @ 600x600dpi in X&Y & 1600dpi Z axis (.0006" Z layer thickness)
Envisiontec Perfactory Mini Multi Lens is the best in my opinion with an astounding 1400x1050dpi in X&Y axis & .0006" Z layer thickness
The Z axis resolution (horizontal layer thickness) is the most critical for highly detailed models to avoid “stair step” effect. You can see that the Objet & Envisiontec Z resolution are twice the Invision. Problem with the EnvisionTec machines is they are hard to find service bureaus running them.