This is a very difficult question.  Sigma Labs ha

This is a very difficult question.  Sigma Labs has made significant progress in the 3D sector in many ways established companies have not.  Greg Morris even credits Sigma Labs for their technological contribution to advance metal AM at the TCT conference:

http://www.youtube.com/watch?v=W_Rw63GIxnM&t=20m57s

No printer maker has been able to create machines efficient enough to begin the process of metal fabrication now.  It also seems as thought Optomec may lead every other printer makers in winning 2 categories for the America Makes award:

https://americamakes.us/news/item/475-second-...l-awardees

The PPS for SGLB was in the mid .20's in December and that is where I think we should be and progressing higher.  GE recently announced that they will be 3D printing fuel nozzles for gas turbines:

http://www.reuters.com/article/2014/01/23/ge-...ompanyNews

PrintRite3D is the only closed loop control and certainly would be required for efficiency.  Not too many investors take the time to understand the process of 3D printing and do not realize how important a closed loop processor is.  Fortunately, Greg Morris, Prahbjot Singh, and America Makes does and PrintRite3D will soon be distributed internationally in areas for supply chain with funds supporting Burke E Porter and Techsolve.