Many 3d Pritner MFG are claiming we are so fast etc etc, sure some are fast, however in reality to be noticeable fast, the quality needs to be good also.
Certainly many factors needs to be considered, however as of current if your machine manage to make the liquid to solid form (with really good quality, no blobs or other strange thing) in less than seconds and have hardware that can calculate those fast data, we will see a winner. 20 cm may take 50 hours to print with very high detail. Do teh same job in 5 hours and you will sell like crazy.